It gets even wilder if you're in California or another Socialistic state.
You buy a basic tractor rig here in-state for $15k and spend $20k on basic upgrades/rebuilds (suspension, tranny, engine if needed). You pay the yearly "road tax" only based on the initial purchase price of $15k - that's 2% of $15k - $300. Register it as a motorhome in-state.
Or you get a GOOD rig, needs nothing, $40k or so like those Volvos wazzizname here on the forum sets up. Fine. $800ish a year ain't TOO crazy.
Send the critter to Showhauler or similar 33ft garage motorhome chassis runs about $125k or so (flexible with various options).
If you started with the basic $15k unit, back in Calif you'll only pay $300 a year to keep it on the road.
Buy the WHOLE thing from Showhauler, with brand-new tractor, etc. at $200k, you'll be paying California DMV $4000 a year for the rest of your life!
Holy crap. That's on TOP of this Federal tax issue.
Solution: whatever you do, get a rig in California that's got a sleeper. Register it as a motorhome, THEN send it out-of-state for "improvements" (big, BIG improvements!).