Personally, I’d go Vaya over 520 for the riding you’re describing. It’s meant for lighter touring, whereas the Trek is designed for a little heavier touring. Generally speaking, the Vaya will therefore handle a little better and be more fun to ride. As for upright position, talk to the bike shop about putting on some nice upright bars with some back sweep, and probably MTB trigger shifters when you buy the bike. If you have them do it then, they shouldn’t charge much for the swap. If they do want to charge you for everything, make sure you get your other parts that would have come on the bike. If the bike comes with road shifters and brakes and they want to charge you regular price for the MTB parts, you’re still paying for the original parts when you buy the bike. You can then resell those parts to recoup some cost. They should give you a heafty doscount at least, though. Another nice thing about swapping to MTB brakes and shifters is the general consensus is that MTB disk brakes work better than road disks with drop levers.

Another option to look into might be a “gravel” bike. Naturally, they’re great for rail trails and most will take a rack and handle a light load just fine.