Anyways, part of me is really torn because I have a solo album that's about to be launched. At the same time, I got asked to audition for a tribute band.
I would audition for the tribute band, but not yet make any decision. If you don't get the gig, you don't ever have to look back. And you gain the experience plus possibly a few worthwhile contacts.
I've been in your position many times, and wonder some days if I might have made better choices. My music career has been up and down and all over the place, and I'm currently in school to be a health counselor. In my training for that it is emphasized that we develop a very clear single focus. I was advised the same 10 years ago in my music career and didn't listen. I had steady gigs, was touring other countries in someone else's headlining band, had 3 CDs of my own music that was gaining some local recognition - but I held on to a flexible day job because I wanted the safety net. I was advised to dive completely into the music, and give that my everything - but I felt I wanted/needed the financial security. I don't actually regret my choice as I'd have probably been a stressed out useless mess if relied on only music, but there are definitely a handful of things that looking back I would have passed on, or done differently.
A happening cover/tribute band could open tons of opportunity for a solo career. It could also squash it dead instantly, depending on what would be required of you. If in your shoes I would get crystal clear about the rehearsal schedule and gig calendar - see how that fits in with the rest of my life - and then decide accordingly. As I said in my first post, if they rehearse weekly and gig every Friday and Saturday then there's little doubt that your solo career is going to get put on hold. Or suffer greatly, to say the least. As I'm writing, I'm realizing there are a plethora of things to consider... too many to write here for sure

. I'd get some paper out, jot down all the pros and cons I could think up, keep asking others what their experience is (not their opinions), and keep in mind that even if you do it, it doesn't necessarily have to be forever.
The one thing I will never do again is get involved in a band with a lot of talk and promises, but nothing concrete to show for it, ie; The guitarist is best friends with the owner of the top agency and as soon as we have 2 solid sets they're going to hook us up with regular gigs at their best clubs. Even if that best friend agency guy tells me himself, which has in fact happened. I'd also keep my ears wide open at the audition, and make certain I wasn't lying to myself about what the band actually has to offer. Trust my gut a little more than I have in the past. And ask lots of questions.
Good luck, with whatever you decide.