first job is storing it properly. We bought a tyvek cover (texas sun is intense). And we will research how to make sure it stores safely in between trips. Seems emptying the tanks makes sense = but do we keep things a bit open, rather than sealed tight -- such as the black water tank? Gases need to escape, right?
1st.. Do not leave your black water tank cracked open.. As you "WILL" forget before you take it out of storage and sewage will leak on the roads. My tank never drains completely. Besides there is a vent for the black tank & grey tanks. It's hidden in the walls and exits on the roof. Much better higher up than ground level.
2nd.. Good idea to cover it from the sun. I've always believed in covering trailers in storage and I can always tell ones that haven't been. ie.. Mine looks brand new.. You may want to figure out some sort of wheel covers as the tires would be the only other concern. I don't do this but where I store my trailer, sun cannot hit the tires.
3rd.. Humidity.. I know this may not be a huge problem for you, but the only thing I do is crack the roof vent 1/2 a turn, before I put the trailer cover on. No condensation buildup at all.
At any rate, welcome to the site & enjoy your new camper.. Oh yeah. And just in case no one told you yet. Do not get frustrated with the trailer. Alot of people buy a new trailer and expect it do be like a car. Perfect. Well.. It's not going to be. There will be things that go wrong with it for the 1st year. The best thing to do, is make a list, If It's something large, like leaks, fridge/a/c doesn't work take it in as soon as you can. If it's small (like trim, decals) just make a list and at the end of your season, bring it back to the service dept to get everything fixed. Not trying to scare you just letting you know that everyone goes through this the first year, And it always gets better.