Yeah, in the perfect world or Baja racing, you'd want four shoes on the ground all the same. Since this is a toad, handling characteristics aren't that big of a deal. Besides, with 400 over GVWR, you aren't going racing.
14" availability: AFAIK 14" LT tires are scarce or nonexistent. There are the Euro van/truck tires available in 14" and I know some Forum members have used them with success. If you can, check out online tire vendors/mfg's to get correct fitment with vehicle and also, rim matching. There shouldn't be any huge issues but best to check diameter of tire and rim width before arriving at tire dealer only to find that you need new rims, also.
I shouldn't have to even say it to an old hand like yourself but spread that load out, fore-aft for the best experience.
