suggestions along I30 in tx

We like Bob Sandlin, though we have never "camped" there. But for an overnight closer to the interstate, there is a nice park in Mount Pleasant:

http://www.ramblinfeverrvpark.com/

You didn't ask, but allow me to comment. If you are going TO Denton you will just have to endure the traffic and stop lights between McKinney and Denton, BUT . . . if Denton is just a way stop to the northwest it would be far better to stay on US 82 all the way to joining US 287 near Wichita Falls.

Please forgive if this comment has no relevance to your question, but maybe it could be of help to others comparing routes across North Texas.

I’ve stayed at Cooper Lake SP along the route you’re looking at, Dangerfield is a very nice park also. If you’re just looking for a place to spend the night Bob Sandlin offers easier highway access.

Just south of MT.Pleasant is Bob Sandlin State Park on Bob Sandlin LAke and also near there is Walleye Park on Cypress Springs Lake.
Short drive. South of 30 from either MtPleasant or Mt Vernon.