Congrats on the purchase.
1) Hook up the sewer compartment
2) Operate the overheadbunk ( ours worked with or without key)
3) Windshield Wipers and washer (Ours had fuses blown)
4) Speaking of fuses there are 4 sets (have the dealer show you) Under fridge, drivers pedal area, engine compartment, left front exterior compartment). The manual does not tell you what is where.
5) Ensure all tires valve extensions operate properly (replaced one)
6) have water ready to go, sinks flow, water pump works, toilet flush, hot water gets hot on gas/then electric. (ours made a noise, fixed quickly)
7) HDMI works on outside TV and location of hookup for RCA/HDMI cable)
8) Recall on step completed
That should get you started, if you have any more questions I will be checking in to see if I can help.