Help getting back into shape after 10 years

I found a local funk band that I want to join. They sent me their set list (like 20 songs, will probably be about 90 mins per show). Problem is, I haven't been playing consistently in like 10 years so my chops are pretty shot and my range is really bad now. Like I'm having to put a lot of effort to play notes above a middle C.

My question is how would you go about practicing to get back into shape for this? I only have about 30 mins most days so it's feeling overwhelming to not only build my chops back up, but also actually learn the songs themselves. What would you do?