Camping opportunities vary across the country.
The Northeast has limited camping because of urban development, but still has some state parks and mostly private, expensive camping.
The Pacific Coast is developed, but has excellent state parks with designated hiker.biker camping.
The Intermountain West has nearly limitless federal lands with campgrounds and dispersed free camping
The Great Plains and Upper Midwest have limited federal lands, but lots of city and county parks with camping.
The Southeast has fewer federal, state, and local facilities, but moderate access to camping.
Texas has the least of all.
And the Southern Tier has 1000 miles in Texas.
The ACA maps have lots of camping places listed, but Texas is more challenging - requiring planning.
I would not stealth camp in Texas or the rest of Dixie - guns & "stand your ground" laws.
Also, in today's immigration climate, stealth camping near the border may be risky.
And, absolutely, do not stealth camp on Indian reservations.
Here is an interactive map of U.S. public lands.
https://blm-egis.maps.arcgis.com/apps/webappviewer/index.html?id=6f0da4c7931440a8a80bfe20eddd7550Take the time to learn what lands allow what. Generally:
National Forest Service (USFS) - anywhere
Bureau of Land Management (BLM) - anywhere
National Park Service (NPS) - designated sites only
National Wildlife Refuges (USFWS) - very few sites offer any camping
Bureau of Reclamation (BuRec) - designated reservoir sites
Army Corps of Engineers (COE) - designated reservoir sites
State public lands - varies by state, limited
State wildlife areas - varies by state, some camping i.e. Texas
Have a great trip.