I have asked this question myself as I am 55 and my health is not good, yet I am determined to do it anyway. Here is what I learnt about SOLO motel touring.
If you have buckets of money to throw about on first-class Motels/Hotels read no further you wont have any problems, but for the rest of us....
The cheap Motels in towns are often located in undesirable areas and the adjacent rooms are often rented by the hour which can disturb your sleep.
Older Ma and Pa Motels in rural areas can be quite OK.
Both of the above rarely get below $35.
You will meet far fewer people when you stay in Motels of any kind and hardly any fellow cyclists as most cyclists stay at hiker/biker campgrounds.
Do'nt stay at RV parks unless you want to be kept awake all night by Redneck beer parties. (Pitching your tent conveniently close to the toilet/shower block may seem like a good idea, it's not.)
The more expensive the Motel the less chance they will let you take your bike into your room. Ask for the laundry or storeroom as an alternative. (Make sure the manager knows you want to leave early.)
Read 77 year-old Earl Norman's tour diaries featuring motel touring (particularily his Lewis + Clarke tour) for a good idea of what to expect.
http://www.crazyguyonabike.com/journal/author/?o=aw&author=bikerearl&v=11j
I hope this helps, see you on the road.
Skymax.