Years ago I stayed in lots of motels when delivering travel trailers. What I did was PLAN my stops and CALL and ask about their parking when making my plans. In most cases, the front desk knew whether or not a TV and TT would be OK. And, like BuddyRay said, lower priced places away from major cities often had parking for big trucks and RVs. Like waggs999 said, Google maps often helps, too, so if they said there was no problem, use Google maps to see if you agree with what they said.
I suggest, too, that you plan to STOP EARLY. If you're there before other folks, you'll be able to pick your parking spaces - not take what might be left. It also gives you the chance for a plan 'B' for the night, if needed.
Next, when parking in the lot, I suggest you plan your parking to be sure you have room to LEAVE when the lot fills up.
In general, where the terrain is open and flat, usually I had little trouble finding motels with sufficient parking. Where the area was hilly etc., all parking lots tended to be smaller.
Sherm & Terry w/rescues Steve (std Poodle) & Eydie (min Schnauzer)
2015 Jay Flight 27RLS (Camped: 102 nights 2015, 90 nights 2016)
2006 Ford F350 6.0 PSD, Lariat, 4WD, CC, LB, SRW, auto., Camper pkg.