Believe it or not, a one-way auto rental may be cost competitive with train or bus. It depends a lot on the current maldistribution of vehicles for the agency you rent from.

You do have to do the driving yourself, but you can stop anywhere you want, enjoy the scenery, plan in an extra day if needed to take in a sight or two or just to gather strength for the rest of the journey.

If you're returning, with a weekly rate it might solve your problem for the whole trip, and you'd have the use of a vehicle while at the other end.

No guarantees on this, but a friend has done it for Texas to Florida trips a couple of times recently, and claims to have "beat the cost" of alternative means of transportation. It would only take a phone call or two to check it out, if it might be of interest.

West coast to Detroit will likely be about 40 hours actual driving time with added food and potty stops, and sleep as needed. (My DeLorme route planner says "quickest route" is 39 hours Los Angeles to Detroit, 2282 miles.)

Forty or so years ago, I found the transcontinental bus service much preferable to rail. The scheduled time was longer, but the actual time was about the same or a little less, since on one rail trip from Kansas to Massachusetts the train was 23 HOURS late. The bus then was about half the price of the train (which was half the price of the cheapest airline). I don't believe any of the bus services have been running any thru (express) buses for at least a decade or two though, and I wouldn't expect a trip on local buses to be much fun.

John