Travel. Don't sit in one place all the time.
We've done volunteering in national and state parks for 2 months at a time but not constantly. Choose an area you want to explore more in depth and apply. Campground hosting is not the only thing. We did lighthouse tours - an awesome way to meet people; gets you outdoors and fascinating history.
Hiking and 4-wheeling with groups was also an interest of ours. Geocaching another.
If you want to stay in one place for a few months in winter consider staying at one of the Escapee-owned parks. They have lots of activities and you can create an activity if you have a particular interest. You'd be surrounded by full-timers and have a lot in common.
If in a area for a while volunteer in the community. I even helped out at the local school with one-on-one in the early reading program. It made me feel good to see the 'light' come on with the children when they discovered they could read.
There's no reason to be bored!