First: Increase staff for maintenance, such as making sure cars/toilets are kept clean during run. Improve quality of food in cafe cars. Increase staffing in dining cars to increase revenue.
Next: Renovation/New equipment acquisition on regular rotation. (I believe I've seen 30 year replacement cycle with a 15 year midlife refurbishment.)
Next: Implement all proposed HSR improvement for NEC; Take over Metro North and rebuild NYP-New Haven to allow 125 mph running (or at least something faster than driving.) Thus, two routes NYP-BOS.
Next: NEC-ify other suitable corridors with at minimum double tracked electrified 125 mph service with min of 12 trains each way daily: Empire (NY) corridor, WAS-NC corridor via Richmond, "Texas Triangle" (Houston-San Antonio-Dallas/FortWorth), Lincoln Service (CHI-STL), Wolverine (CHI-DET), Chicago-Toledo-Cleveland, Toledo Detroit, Cleveland-Columbus-Cincinnati, CHI-Milwaukee-St Paul, Cheyenne-Denver-Colorado Springs-Albuquerque, Portland-Seattle-Vancouver
Next: Open a corridor from Washington (and the NEC) to the southeast on the western slope of the Appalachians - WAS-Knoxville-Nashville or Atalnta. Also a corridor from Chicago to Nashville and Atlanta, and Atlanta-Savannah, Also restore service from the Northeast to St. Louis.
Next: Cover the country with network of "short distance" (<600 mi) corridors that all interconnect. Non-NEC-fied corridors would have daily frequencies of 4-6 per day. In addition to providing useful transportation alternatives, this would greatly decrease the incremental cost of adding long distance trains.
Next: Upgrade some of the NEC-ified corridors to true high speed rail. Which corridors would depend on market conditions and other factors in place, like the development of denser transit-oriented urban development, transit connections, local interest, technical feasibility, etc.
For long distance train service: twice daily frequencies on the busiest routes. Additional frequencies on parts of the routes to ensure the entire route has some sort of usable service. Nobody should be in the position of a city like Cleveland, OH, where all the trains stop in the middle of the night. I would want to bring back the vista domes on at least some routes, and also some sort of budget-priced lie-flat sleeping option.
International Service: Restore the Montrealer/Washingtonian, and also extend the Adirondack to Washington (which was done for a while in the past) Also, tighten the scheudle of the Maple leaf to allow a decent connection to/from Philadelphia and Washington. Boston-Montreal Service. Restore the International between Chicago and Toronto, and provide Thruway bus transfer from Detroit to Windsor (or maybe even run the International through Detroit and Windsor, I think there's a rail tunnel under the Detroit River.) Portland-Vancouver. On the southern border, an international train from San Antonio -- Laredo--Nuevo Laredo- Monterrey and maybe even Mexico City.
And, of course, a budget o buy all the equipment and track upgrades to run these services.