Book in Advance - Since we knew the event we were going to was going to be huge, we booked a year in advance. That might seem excessive, but it's better to be safe than sorry. We had mutual friends look for an RV 3 months before their trip and everything was booked. Of course there are busy seasons and not-so-busy seasons, but I wouldn't take any chances. As soon as you know you want to take the trip for sure, book!
Everyone Should Pay Attention to the RV Walk-Through (or have everyone read the manual): When you first pick up the RV, especially if you're a first-time renter, you'll be given a walk-through of the RV to make sure you know how to use everything. You'll also be given tips and tricks on how to make your trip seamless. Make sure everyone is paying attention! We only had about 4 people there for the walk-through, so those 4 other people were clueless when we hit the road. If they miss the walk-through, have them flip through the manual. It's way better for everyone to know what's going on than just a select few.
Do secure EVERYTHING, even inside the cabinets - We thought we did a great job securing everything in cabinets and on the tables, but as soon as we started driving - it seemed like everything was flying all over the place. Make sure you secure EVERYTHING. If you have items in cabinets that are standing up, lay them down because they are going to tip over anyway - especially if its glass. We found out the hard way when we put a box of beers on the floor that tipped over - glass and beer went everywhere!
Bring Cleaning Supplies - We only brought a few paper towels, wet wipes and some dish soap, but by the end of the trip we had stopped at Walmart to buy a broom and three packs of Lysol wipes. Even though we spent most of our time outside, the RV got REALLY messy inside between food prep, late night shenanigans, and just the general dirt that seemed to sneak in.
Prepare to be Smelly - Any small enclosed space shared between 8 people is going to get a bit stuffy, but once you throw in being pretty inebriated all day and night, it's bound to get smelly inside. So, remember to keep the windows open every now and then to air out the space and bring some Febreeze! And as much as you probably don't want to, cleaning as you go always helps.
(Depending on your RV) There's More Room than You Think - I was pleasantly surprised at how much storage space we had in our RV. Between the outside compartments and the indoor organization, it was really a breeze to fit 8 people's food and personal items. I'm not saying to over pack, but just don't worry too much about the space, RV's are typically built to hold a lot.
So overall, I would definitely recommend renting an RV at some point for either a big event like a music festival or just a quiet camping trip. I think we'll definitely be renting one again!