@Maggie Blackham, we put in RV hookups for the tiny houses. It was about $23K for us to put in a gravel road, run electric & water, and put in a small septic system for 3 houses. Even though the tiny houses are on wheels and are fully functional RV's, we have no plans to move them. We even built porches onto them, so they aren't going anywhere unless we decide to sell them or to move them permanently. Initially, we connected the houses to the septic with RV sewer hose. After dealing with the hoses leaking, not draining properly, etc., we caved and spent $1,500 to have PVC waste pipe installed between the houses and the septic system.
You can see more pictures of the houses here: https://www.airbnb.com/rooms/14282082 and https://www.airbnb.com/rooms/13248492 .
One update from my last post - bookings have picked up significantly. We haven't raised our rates much, but have learned some pricing tricks. We set the "base price" low, then raise prices for weekends. This seems to bring in more multi-day stays. Also, we've built up a base of good reviews. So, our numbers are definitely looking better this year.
It hasn't been all sunshine and roses, though. We've had lots of trouble with the plumbing backing up on one of the houses in addition to the previously mentioned sewer hose problems. Listening to so many BP podcasts has been helpful in dealing with this. I just shrug my shoulders and say, "tenants and toilets".