https://travelmapping.net/user/mapview.php?rg=THAtham and thaexat (motorways and expressways) should be complete. thasf is not yet complete, and thatp (federal highways) has all 1-3-digit routes, but 4-digit routes are very incomplete for now.
If you have existing travels in Thailand, please see
the thaah thread for details on Bangkok-area changes.