At 5'10-11, three of my bikes have top tubes of about 23 inches, so this is clearly too small for you.
A good friend of mine is about your height and I think rides a 60cm frame, and could have it a bit bigger--but in the end, stem choices make up a big difference with a few cms here or there making the diff.
check out this general chart that shows the range ish of frame sizing to people
https://surlybikes.com/uploads/downl...hart_OL_VF.pdf
in any case, you could easily get a stem that is the right length in the vertical, but with a longer forward part, or go the route of the vertical only threaded to threadless or whatever its called thing, and then be able to switch and try diff actual stems until you find a length and angle that works.
plus, you are also trying to get into regular riding, so with a few parts, you could make this bike be fairly close fit wise, and concentrate on getting out regularly and build up fitness and endurance.
and then if you really want to continue biking and maybe tour again, you'll have a much better idea of what works for you if and when you look at another bike. Large and extra large used bikes are less common, but again, can also perhaps find a good deal because of the fact that they are harder to sell.
Anyway, thats down the road.
tire, there are so many good tires out there, visit a good bike store and they can recommend stuff.
You should be able to put on a reasonably priced rear rack also, and hopefully not have heel strike problems, but hard to tell given that its a small frame for you.