I've done I-70 and I-40 routes. I-70 is really beautiful through Colorado and Utah but be prepared for plenty of grades in the mountains. Plus you get to stop in Las Vegas going that way! You can also cut through Death Valley going into CA. I-40 is much flatter for a big truck, you still hit some pretty high elevations, Flagstaff is 7000', but nothing too bad. Be sure to stop at the meteor crater going that way. I can't help you with CA, went there once, you can keep it. Hated the traffic.
I would agree you are not allowing enough travel days. In my experience towing, I average 55 mph on long hauls, and that takes into account gas stops, reasonable lunch stops, etc., but you gotta keep your butt in the seat and rolling or you won't even average that much. Indy to San Jose is 2300 miles which would be 42 hours driving each way. That makes 14 hour driving days with no extra stops. That's pretty ambitious unless you drive for a living or are 25 and live on energy drinks. Our longest haul towing was Ohio to Las Vegas in 36 hours drive time switching drivers every 4 hours and keeping it on the wood. And that was when we were 30 and lived on mountain dew. That's about the same distance as you are going, and that would be 12 hours a day and like I said, we had it on the wood and no scenic stops.
Good luck and enjoy!
