There are lots of options and none will disappoint as far as scenery goes considering that you've not hunted outside of Indiana. However, there's nothing wrong with an Eastern gobbling on a hardwood ridge (I miss it every year that I can't go back home in the spring).
As some have stated Colorado mountains make a beautiful backdrop for hunting Merriam's. New Mexico and Arizona (not sure if AZ has OTC tags) are likely beautiful places also, but I've not hunted there. Northwest Nebraska is fun and I love it there but the pressure has increased through the last 10 years. South Dakota and Wyoming Black hills look beautiful and there's a lot of touristy stuff close by for the rest of the family (You do need to order these tags but it isn't a lottery). Montana has some nice turkey country and multiple OTC tags but most of it is in some really secluded places and you'll do a lot of traveling just within the state to try and fill tags. Northeast Washington has some great hunting but I've only been there once. Idaho is always on the radar, but I've yet to hunt them there.
Biologists and Wildlife officers seem more than willing to point out areas with turkeys. I know some of them here in Montana aren't terribly familiar with turkeys, so you may have to try more than one phone number. Also, most western states have distribution maps that show where the turkeys are. Western states don't necessarily have continuous habitat suitable for turkeys.
