Randy,
All the things you mention are things I'm going to thinking over carefully as I look to register a MH, and yes - Wyoming. The county controls vehicle registration here and it's a circus. First you go to titling department and they title the vehicle - then you go to licencing and they sell the tags. Licencing decides what tags/application they are going to sell you, but they won't make a decision until titling has done their part. Ttitling won't budge - their opinion is that it was built as a tractor - it's always a tractor. Licensing says that if it's a tractor it's commercial.
If that isn't bad enough the fees are based on the original MSRP and decline by 6% per year. A co-worker pays $2400 annually right now for his class A MH. If If I based my registration on a 5 yr old HDT, I'm not sure I want to know their fee. MY 5'er is an '07 TH and it was $580 for this year's tags.
When you say states are checking for out of state registration I'm guessing you mean that my residence state is checking to see that my MH wouldn't be domiciled at home yet registered in Montana. I can't imagine it making a difference to Colorado or NM or AZ if I live in WY and drive a vehicle from MT. The answer to that is simply to domicile the RV out of state in order to comply with the registration requirements.
It would be a LOT easier to register in my local county and I do have the county treasurer's # to call and contact as I get closer to a full on project. The funny thing is - the neighboring county has a person that operates an old HDT as a personal vehicle - but that county says that if you don't live in the county - they can't register your vehicle.
There are plenty of ways to work this out. I just haven't found which one I'd use yet.
Thanks for your input.