Stosheroo

I just bought a 1988 Trek 520 frame and am getting ready to turn it into an everyday bike for riding paved bike paths and mostly flat, paved back roads. I may also try my hand at short, lightly loaded credit card touring. I’m an old guy (71) in decent but not impressive shape, and don’t plan to ride up big hills. I just want a more relaxed, comfortable bike to ride with my buddies who are about the same age as I am, and in about the same shape. My initial thinking is to equip it as follows:

· Shimano 105 5700 RD, FD, triple crankset, 36 hole rear (11-28) and front hubs
· Dura Ace SL-BS78 2/3 x 10-Speed Bar End Shifters on Paul Shimano Thumbies
· 700c rims with 28mm road tires
· Velo Orange Crazy Bar

Note
I had these shifters left over from a previous project and want to put them to use instead of buying new shifters. Drop bars have become pretty uncomfortable for me so I’m looking for a more upright riding position with easy access to shifters and brakes.

Is there anything here that could get me into trouble, in terms of compatibility or otherwise?

Again, I’m not trying to recreate the 520 as a loaded touring bike but as a comfortable bike for riding mostly paved bike paths and back roads with modest hills here and there.

Thanks, in advance, for any perspective and/or advice you can throw my way as I begin this project.