Your OP contains good ideas to develop but I'm with guest,mg: Get out and perform now. Get started trying different locations at different times to learn the people-traffic patterns and tastes--maybe Blantyre Explosion at one corner and Hey Jude the next.

There IS one notable damper on my own enthusiasm for you using a 25-lb-anything to busk, and that is your hernia. A 2-compartment backpack can fit washboard & uke and smaller stuff, and be light enough not to be a hernia risk--make sure to add an extra-long waist-strap to accommodate your girth, so your hips will take most of the weight.

Maybe there are light-weight ways to evoke the medicine-show era. A balloon-sleeved shirt under a contrasting vest could be one way. Maybe develop the trunk-based medicine show idea to use after your hernia surgery? I know you'll put it on wheels, but what is your "doctor's orders" lifting limit, and who will lift the 40-50 lb wagonful of instruments in and out of the car for you? Up and down the porch steps of the house? Something that's very clear, though: Your enthusiasm to develop your medicine show vision tells me your creativity truly needs an outlet, so honour that need, but preferably while excluding medical risks.(If you live at walking distance from busking locations, cancel that whole issue.)

Setting aside all the trappings, I expect you will be just as entertaining if you wear a pressed shirt and bright-ish yet tasteful tie, tidy dark pants and dress shoes. In other words, be well groomed with a non-threatening, middle-of-the-road style. Then your music will speak. If you sing the song-stories from your heart and reasonably in tune and look your audience in the eye, people will respond.