That does look quite a decent deal based on the pictures. You should be in for a lot of fun adventures! With even the tiniest bit of luck, the memories and good family relationships will be worth far far more than you'll ever pay in money.
By the way: assuming it has typical electric brakes, you need a battery to be legal in most places with an emergency disconnect brake. This is a system that automatically applies the trailer brakes should it become disconnected from your tow vehicle somehow, generally by having a lanyard of sorts that is attached to the tow vehicle and pulls out of a special switch on the trailer. When the lanyard is pulled out, the switch turns on the trailer brakes using the trailer battery. (This also means that the disconnect lanyard must be plugged into the trailer properly whenever you have it parked or the battery will rapidly be discharged from the brakes being constantly applied.)
I suggest looking over the roof caulking carefully where the front and rear panels meet with the roof and where there are things that protrude through the roof. The standard material to use here is "Dicor self-leveling lap joint compound." Any that is cracked should be cleaned and covered over with fresh before it leaks. Also look over the other caulking, around the marker lights etc. Perhaps the most popular material for these is "Geocel pro-flex RV sealant"; avoid silicone based caulks at all costs. (Once cured, pretty much nothing adheres to silicone when it needs to be touched up/redone, including more silicone, and it's very very hard to get all the old silicone off to reseal.)
Checking and sealing stuff on RVs is a periodic routine maintenance necessity, one of those things that's not particularly fun but needs to be done. It takes a comparatively short time for a leak to do costly damage to most RVs.