OK realistically.

You are talking about setting the house up for some "extra guests" or "travelers"

If you are in a rural area, think about setting up outbuildings to double as living space. Barn attics and additions usually work pretty good for that.

In rural areas especially, but also in some urban areas you can do this - install extra bathrooms in other buildings. A bathroom in a garage, even if it is just the toilet and sink type will help. You can also put in "worker facilities" in most barns and industrial buildings without a whole lot of permit hassle.

For spare beds, think the narrow twin beds, or bunk beds. Again, we are not talking major work for a barn attic conversion. We ended up finding couches easier to obtain in better condition. Although harder to move into location, they just seemed better for multipurpose utility in the rooms and held up better.

Think large covered parking spaces, as one option for concealing the population on a rural property is to simply pull RVs and "live-in" type vehicles into the barns.

I have worked on projects where we have pretty much done all of the above at one time or another. The barn conversion is one of the more "property owner friendly" situations. We drywalled in a large side room of a barn and then collected up a bunch of free furniture to furnish it. Installation of the wood burning stove was fairly easy. The only thing that was somewhat mickey mouse about it was the improvised plumbing. It was all done with garden hoses from the main house due to permit issues. The toilet situation was a composting outhouse about a hundred yards away and a porta-john on the other side of the barn next to the one with the live-in conversion (we did not want the smell drifting over, hence it was some distance away which was unpopular in bad weather).

Food storage was done a number of ways. One, the people who were "travelling" were expected to pitch in somehow, and the easiest way to accomplish that was to not arrive empty handed. If someone was there for any length of time, they were expected to at least check in at a local food bank or something. As it was, the main people living there, especially the main guy, was a bit of a hoarder, so the place was usually pretty well stocked with canned food and slightly out of date boxed food. If travelers rolled in with meat, beverages, and some cleaning supplies, then that was pretty welcome. Permanent residents of the retreat usually had fresh vegtables covered from the garden.

We had a lot of chickens around, but not too many people had the hear to actually kill any of them, especially when some of the girls became attached to them as pseudo-pets. My bayonet practice idea, mentioned as a half joke one night at dinner did not go over so well. Well, at least not with the chickens. Wild hogs ruining the eh, special gardens were another story. Killing them quietly was an activity worthy of a modest bounty.

Another issue for the safehouse is concealment of vehicles. Parking gets to be a real issue, and you have to look at how the opposition is going to treat the presence of extra vehicles. The retreats I was involved with all had lots of extra vehicles on site, where one or two more or less was just not going to show. My last place had spots under trees that I had trimmed out in a park landscape style where the parking space under the trees was pretty big in some spots. someone would be able to pull into the property, make a few turns and be out of sight and out of mind. I also kept some camo netting around for concealment of vehicles if needed. Another option was just to have a plan for shuttling people to and from vehicles parked down the road.

You want to be able to handle the people's water needs. Water storage is not incredibly difficult, but also think extra hoses that can be hooked up to campers and RVs, and having a full-on RV hookup or two on your property.

Likewise, electricity. Be prepared to go into 'high efficiency mode' when people arrive if you feel there might be a need to conceal the utility use when they are around. It might not be entirely necessary but depends on how long they will be around. You might also just want to get all of your neighbors and utility people accustomed to the higher power usage. Going into high efficiency mode though, that means unplugging some high power usage equipment like freezers, extra refrigerators, extra high wattage lighting and electric heating (electric cooling tends to cost the same no matter how many people are around). If you normally cook with electricity, just be prepared to fire up the grill.

The extra freezers and fridge get plugged back in right when everyone is going to sleep and turning the lights out, as that will even out the power usage and reduce your chances of blown breakers.

Don't forget extra dishes, toilet paper, and big cooking pots for larger group meals. The meals can be fairly simple, and for short periods can be power usage intensive.

Trash removal is another issue. Food containers, toilet paper, (ammo boxes) and cigarette butts, and other waste material becomes an issue. Have some boxes of big heavy duty disposable trash bags around. Realize that one task that someone gets stuck with yet is fairly important is hauling garbage out. Paper and wood can be burned, biomass can be composted, then there is the plastics. Also consider how to get rid of or destroy "evidence garbage" such as boxes and wrappers for ammo, batteries, specialized electronics ect.

Some of you might notice this follows a pattern called SWET (Sewage, Water, Electric, and Trash). These are basic needs for housing troops, as improvised shelters and bedspace are often a matter of how much discomfort the people might be willing to endure.

Prepping a piece of real estate for that situation means adding restrooms, electrical outlets, plumbing, and garbage removal.

Realistically, and for tactical realities in the US, it also means having a parking plan and the means to handle additional sleeping area. This can be as simple as scouting out some extra parking on or near your property, having some spare couches in the garage, and spare electrical outlets that can be run out to some "campsites" around your property. It means having the barbecue grill ready to roll, and even though you may not keep a beef quarter in your freezer, having spices and condiments around for a "get together" can help a lot, likewise simple stuff like extra plates, glasses and silverware.

Property improvements mean little studio apartments here and there, mostly hidden, or set up in such a way that it is difficult to tell if someone is living there or not. Note, it is entirely appropriate for these studio apartment type places to be unfinished, and for the residents to be expected to provide labor in working on improvements. Plaster, flooring and drywall work tend to be fairly labor intensive, but not incredibly expensive on materials. Safehouse residents can do that work, so it is appropriate for the safehouse host to just obtain the materials and not have everything set up like it is a bed & breakfast, but over time and use, a safehouse would end up functioning like that.