That's what I did pretty much.
The Resolutes are a rad tyre - I find they actually roll real fast because of the tight 1-2-1 knobs down the middle (which is very similar to the Compass Steilacoom wet weather tyre). I use this for lots of singletrack and gravel rides that have some decent chunk. The 42mms fit in my Escapade with a few mm clearance to the frame (so no issues for the alloy frame).
I would recommend some chainstay protection if you're going to ride on singletrack. That Claris derailleur doesn't have the strongest tension spring.
Wheels wise, I would recommend the Hope 20 Five wheels for your 'nicer' set. Hope RS4 Hubs, 32 Spokes, Brass nipples, 20mm wide internal (a couple mm wide would be ideal, but was cheaper than going custom). You can get them from Merlin for $420 USD thereabouts. Good thing is that they come as QR standard, with 12mm thru adaptors for the F and R (you just need the front for your Explore).