Thanks everyone for the feedback! I was already leaning in the direction of option 2, but have definitely learned some things here. Weekender (eventually) sounds good to me.

The derailleurs are both Shimano Alivios. I'm somewhat confused by the information on Shimano's site, but it looks likely that the FD can handle a 48/36/26 chainset. Currently I have a 44/32/22. That should be good enough for me for the foreseeable future on commutes. I don't think the rings on the current chainset are replaceable, and I'd have to switch out all three anyway, which I doubt would be any cheaper. I don't mind spending the money on a new chainset, as long as it's not wasted. Rear cassette is 11-32, 8-speed, which I think is fine and can't get much better. I'd rather not swap out the whole drive train without a good reason, so I think I'll stick to the MTB gear for now.

Greg, how does the fork you linked to compare to the Surly ones? I've seen a bunch of recommendations for those. The one you linked to might be heavy, but from what I've found, it's half the weight of the one I have now My understanding is that I roughly need to match the lengths of the forks, and I measure ~460mm for my fork right now (without sag), while the one you linked to is somewhat shorter. I know the Surly ones are longer than usual - are there any cheaper ones? Bike is a hardtail, so I don't need to worry about the rear.

Thanks again!