We are going into our second year at our seasonal site. We love it and nothing beats throwing the kids and dogs in the Yukon and spending the weekend camping...which usually means going right after the hubs gets home from work on Friday and leaving sometime after dinner on Sunday. The CG does some site maintenance but we tidy up and do upkeep as needed (which is not much). We pull our TT off the site 2-3 times a season.
You have gotten some great advice about turning the water off, bringing awnings in, critter control and when to dump. Some other things we do are:
1. Blow off the slides and bring them in before we leave (we don't have slide toppers....yet!)
2. We have wood boards under the tires and the tires have covers on them
3. Once the water is turned off we also release water pressure
4. Solar lights are placed around our site for a little extra light at night
We have a gazebo and grill. We're looking for a shed to store stuff in so we don't have to worry about hauling it home at the end of the season. I wouldn't recommend going the shed route unless you know you will continue to be seasonal.
Instead of a deck we have outdoor carpet that runs the length of the trailer. The carpet extends to the edge of the awning and is inside the gazebo. We were going to build a deck but getting into and out of our site can be tricky.... running over carpet is better than moving and/or running into a deck (which of course would be MY fault if it happened!) ;)
Good luck and enjoy! =)
Kelly
**Edited to add: We also make sure the water heater is turned off too before we leave.**