I would change the engine and generator oil and air filters, the rear end oil, the transmission oil, and have the front wheel bearings checked. I'd have the brakes looked at and maybe the brake fluid changed. If there's a drinking water filter, change it and sanitize the drinking water tank. Should probably do the engine belts also.
It may not be hot out yet, but it will get there so make sure the dash and roof air working and putting out cold air.
Check the water level in the batteries even if they are new.
If you have leveling jacks, make sure they work well and if you don't, get some leveling boards.
Does the awning work - no rips or holes.
Bill