My elk hunt plans have essentially fallen through after I jumped through hoops to get my vacation moved to elk season.

May be able to talk my uncle into going after antelope. For financial reasons the hunt would have to be DIY, and no guide. Need an area with lots of public access/wmas.

Vacation runs sept6 - 16

I would also like to entertain a caribou hunt but would still have to be in same time frame, and financial constraints

I would think an antelope hunt would be far cheaper than a DIY caribou hunt.

Antelope are cheap and much more easily , accessible than caribou, unless you happen to live in Canada or Alaska; definitely two different types of hunt. Waterholing antelope is pretty successful, spot and stalk antelope not nearly so successful but a lot of fun.
Wyoming usually has leftover tags after the resident draw, which is in July. We have more goats than people in Wyoming!