Overall, I think it looks pretty good Pecha, and also pretty epic. I'm sure this isn't a final route, but if you're looking at tagging all 48, you're missing a few here.
The ones I noticed:
-Rhode Island (shouldn't be hard to add)
-Delaware (same)
-Michigan (just a short detour to the north)
-Kentucky (you just need to get across the river)
-Kansas (cut across into KC real quick, or take a small detour near Joplin)
I think your route looks pretty efficient, but two places I see that could cut some mileage are: 1) Cut through eastern Wyoming into NE Nebraska near Lusk, WY, then head NE on US/State highways through South Dakota and into the SE corner of N Dakota. This eliminates Iowa on the northbound portion, but could be easily tagged going from Minnesota into Wisconsin/Illinois area. 2) Find a way to tag Kentucky heading SW down the east coast, and you can eliminate the large jog north into Missouri (which also seems much longer than need be). If you do that, you can head directly for the Joplin area, passing through Arkansas from SE to NW, then end in the corner getting AR, MO, KS, and OK before heading west towards TX and NM to finish the route.