Okay, first pass, but be forewarned that I'm rather tired from all those crowds and warm, humid sunshine yesterday, lol. OMG, don't kids go to school anymore?!?!
When you are doing your planning, and yes, you should make a plan, shoot, you'll probably make several, make sure you will have room to rotate crops. This should be done on at least a three year cycle. The purpose is to prevent build up of disease organisms, think the Irish potato famine. Nightshades MUST be rotated, this means tomatoes, potatoes, peppers, eggplants, as they all share the same problems.
It is my understanding that herbs don't really require the best of soils. So you should be okay to get started. Watch the path of the sun in your yard. Choose a place (or places) that has at least six hours of decent sun exposure for the herb garden. I had a perennial herbs area, oregano for drying, thyme, rosemary sometimes (depending on the severity of the winter), and dill (which is an annual, but self sows well enough to warrant a permanent location). Yes, mint is a perennial, but it runners big time, and so its aggressive tendencies must be contained. I grew parsley in half barrels, three per barrel. Parsley and dill have tap roots (they are related to carrots), and are picky about being transplanted and about having deep enough loose soil. But it sounds like your sandy would work okay. I always had to tie up the basil plants.
I assume UW Madison has an extension service? Do some checking and see what suggestions are made for your location.
It sounds like it would be wise for you to work at increasing the organic matter in your soil. Is there a place to purchase compost? When we lived in Cleveland, the county picked up refuse in the fall with giant leaf sucker machines and took it to the county composting facility. You could bring your truck and shovel and get fully composted leaf humus, which was really nice. Manure is another option. Buying bagged stuff is more expensive.
Okay, that's it for my brain cells this morning. Oh, with the exception of one other thought, seed catalogs...... Oh, yeah, I got the paper ones, generally came around Christmas. Merry Christmas to me in the mail.
I know they are all available online, but I liked spreading them out on the kitchen table and comparing, deciding, learning. Sigh, I miss my garden!