So far you seem to be doing a lot! Avatar hunting is an ongoing process, so if you're into that then keep pursuing it.
It also really depends what you're interested in. I returned last year and have been enjoying drawing my pets, working on characters for them, etc. So if you're inspired in that capacity I think it's a great way to step into a different creative space and take a break from real life projects, while still being productive.
Playing with CSS is also super fun and a good way to spend time, if you like things like that. Writing is another good option. You could aim for things like Userlookup of the Week, or getting your entries into the Neopian Times.
Honestly, I think what you're doing now has pretty much covered most of what I'd recommend! Putting a few hours max a day is a good approach so you don't get burnt out/bored. Charity Corner is supposedly starting soon(ish), so that will be another thing you can do~