They added my supplied comps and agreed that my comps were correct, but they refused to raise the appraised value.

Supply has gone down.

Once your cars, furniture, and house are paid off you have extra money to keep investing.

Vacation rentals have turnovers every week, people can call you, you have to deal with furniture which has a short life sometimes in such rentals.

Plants and some cheap patio furniture will help. 

Ask yourself this, if you supplied utilities, water,e tc for the tenant and you didn't pay the bills for it.

I assume the comps help but is there anything else you would use to determine ARV, and other than looking at the cost of building supplies, is there any other way to get a good estimate of rehab costs?

But if you just want to measure up your rooms and then experiment with different layouts, furniture arrangements, etc, it's perfect and pretty easy and intuitive to use.It's particularly useful for visualizing your designs and showing them to contractors and clients.

We have found that Laramie can be a very challenging market, partly because of the high demand and low supply of housing.  

How can the Housing "Market" go down, when there is too much demand, chasing too much supply?