If you can only do one, and you are a row crop farmer, Louisville would be better.

Tulare is interesting, but there is a big part of it devoted to dairy and fruits/veggies. Well worth the trip for the experience, but not near as valuable for someone who makes a living raising grain.

Louisville has a good amount of cattle stuff, a small % of dairy, and very little veggie-specific.

Both good, depends on if you are going "strictly business" or just for entertainment.