Michelle, the most likely places for floor problems are under
windows (especially the front) and anywhere there is plumbing. You'll want to bring a flashlight and a screwdriver to poke around the floor inside cabinets to verify soundness.
Next to the shell & frame, the most important things to check are the appliances. Talk to the seller ahead of time to make sure it can be connected to LP and electricity. If it has a
fridge, ask the seller to turn it on several hours before you come, because it takes quite a while to cool down.
If you can't verify the operation of any appliance, or if the seller says "it worked the last time I used it" or (of the fridge) "it just needs a charge," you have to assume it doesn't work and the price should reflect that. (BTW, 2- and 3-way RV fridges don't get "charged," so that's a red flag in itself). Some people replace broken RV fridges with dorm-type units because replacing an RV
fridge can get very expensive. Dorm fridges require camp sites with electric hook-ups, which limits where you can go. Just something to know…
If it has
brakes, it's probably already had the
axle changed, so that's a good thing. If it doesn't, in most cases with an older trailer like a
Boler, you'll have to replace the whole
axle to add
brakes, and the price should reflect that as well.
If you do pull the trigger, there are some important things to check before you tow it anywhere, like
tires and bearings, but those are normal maintenance items and shouldn't have too much bearing on whether or not you buy.