All of the above but start in spring:
1. hit up garage sales, you will need the following:
Plates, silverware, toaster, cups, bowls, welcome mats, etc etc.
If going with a hard side, get a large rug to put down under the awning, like 15 x 30, etc
Get string lights, (christmas lights, etc) and these will go on the awnings
Get a solar charger for the DC battery on the trailer
get a generator, or generators. I love the honda's, but they can be pricey. if you ONLY go to campsites that have power, then that's fine, but if unsure, keep and eye out for a good deal. the honda's are quiet compared to others, and dependable. (I have 2 of the honda's, and one larger "predator" harbor freight one, happy with both"
power adapters, 15 to 30 amp and who knows what else. get the one you need, and then an extra one. keep them all together
Now, as far as size goes, go to a dealer, see what they have to offer, and at least it will give you an idea on what size you want/need, layout that you like, or even a specific model so when you are looking, you
This list can keep going on and on btw...
search up on glamping, sometimes going with a restored "shasta" is worth it, and it's different..
Knowledge base: I go camping 3-4 times a year for the past 16 years. I currently use a pop up, since we always go to the same place. I have worked through hard sides, UL's, etc. We go camping with other family members, who have anything from tents, to Full out RV's with slide outs, etc. it all depends on what you are going camping for... (we go to lake Koshkonong in Wisconsin so boating is a big part of what we do, we are not camping for the "nature" side of things.