Howdy, first, did you get them winders done without too much trouble?
The wasps: Do not seal it all off and set off a bunch of bug bombs. Trailers, and other structures, have been set on fire, even exploded, by using too many in a confined space. Most disasters were ignited by gas pilot lights, sparks at loose electrical connections, but some seem to have been self igniting. But shut off gas line and electric to be safe(r). Best wasp killer I have ever used is "Eco-Smart Wasp and Hornet Killer" works faster and shoots farther than any I've used. Wasps die B4 they can get to you, but then I've never used it in area I didn't have plenty of get away room. Best advice, squirt and run like hell. If under trailer and can get a good long shot at nest, have pre-planned escape route. Tie your ankles to pick-up, get jerked out of there. Tie yourself to mule, wasp stings mule, your outta there and half way down road. You mite can now knock down nests and remove them. Some wasps are not at home, they will come back, if nest is not there, even on ground, they will leave. They don't rebuild cause you killed queen. Or wait for them to return, wader around on nest all confused, "Where'd everbody go?" Squirt again. then knock down.
Vacuum idea is good, takes some time, as dan sed, don't disturb nest. A few light taps when most wasps sucked up OK. But you wind up with vacuum full of wasps. Throw away bag type no prob. Others such as Shop Vac, let vac suck in some pizen, shut off and wait a while. Or reverse vac and shoot wasps at them rock chunkin boys.
You can use the Demon if ya want, but it will kill spiders and lizards and they eat wasps and other bad bugs. I use a pelletized, granular repellent, not a poison, that is keeping nasties away, but the geckos, skinks, anoles and all don't seem affected by it.. I'd tell you the brand name, but the bag is in shed behind a huge pile of cra...zy stuff.
Long stick with coarse tooth sawzall blade on end, or tree pruning pole saw to pull down nests. Don't try to smoke them out, with a smoldering torch, smoke doesn't "calm" them like it does bees, and don't wanna torch trailer. No hose attached to exhaust pipe either. I presume these are paper wasps, yellow jackets or such and not dirt daubers? Dirt daubers usually don't bother you unless you actually disturb nest. Fasten bug bomb to long stick, put directly under nest. Hole in floor, bug bomb in house not gonna do much good. Hole in floor to where you could squirt wasp killer on nest mite. Squirt and cover hole.
Skunks eat wasps. Invite one over. Getting rid of skunk less painful but more odoriferous. Me and mrs had incredible multi skunk prob when we were young, living in place we could afford,. so I can help with that too.
" guy a new trailer" First don't need to, she got a trailer and its already guyed, she has fiance. I really get irked at folks that say "Spend money" Some of us aint got money to spend. Yes, buy best you can afford, do job right way, more than one right way. Cash on hand may not allow "best way". Cash flow schedule may allow "best way" in situation; but"wrong way" that can be redone same "wrong way" periodically may be “best way” Not best way economically in long run, but ... Tore into a responder the other day, who told questioner to buy "right" materials, to "move to USA where materials are available at HD." Turns out questioner was aid/relief worker running refugee camp, trying to make do with materials at hand. Please, when responding, do not make presumptions, assumptions, or holier (and richer) than thou statements. Some of us are on shoe string budgets, if our shoe string breaks and we ask what is best knot to tie it back together, please,don't tell us to buy a new shoestring.
Now, dismounting from high horse and standing on floor. First, “best way” is rip out all particle board, replace with joe's ¾ tongue and groove, glued and screwed ( I have learned not to argue with joe, except for fun) Next is remove damaged PB and a bit of solid, keep cuts over joists and bridging, replace with same thickness exterior plywood, glued and screwed. You don't want to just cover water damaged materials, there's mold and rot bacteria in there that will spread in presence of moisture.. Moisture comes not only from outside, in fact , if crawl space is adequately shielded and vented, vapor barrier on ground, most moisture comes from warm air in living space meeting cool air outside. Moisture from washing, bathing, just plain breathing. Don't know about you and your guy in trailer, but when we were young & living in affordable shack, was some heavy breathing going on, had nothin to do with skunk family.
Laminate flooring is fastened only to itself, “floats” on a thin pad.. There is gap all around, doesn't touch walls. A layer of exterior plywood (CDX orAdvantec) over sound but springy particle board, glued and screwed to particle board and thru it to joists, will add stiffness, but hard to screw to PB. The thicker the better, but I will argue with joe, 1/2” with plenty of glue and screws will work, its done all the time and while not “best,” is “right.”
If you've managed to read this far, you've got the stamina and patience of Job to do the job of getting the trailer livable. I gotta go, I see some boys comin and even if they aint got chunkin rocks, I bet they gonna get on my lawn, I gotta find me a stick to shake at um. Lawn...dried hay, Will it never rain? It can rain now, right? You got the windows fixed? And with shelf liners?