You can use pre-tax "commuter benefits" debit card funds for Amtrak commutes, and there are
10-ride passes available for Northeast Regional trains.
Suggestions I'll echo, as someone who does this trip at least monthly:
- Travel from Richmond (Staples Mill) vs. Fredericksburg, removes almost any traffic tie-ups and still gets 10 trains a day; generally fewer delays on that segment vs. south of it
- Some people on the Triangle forum have mentioned Amtrak from Rocky Mount, which sees 4 trains a day (vs. 2 in Raleigh) and has free parking
- Buy Amtrak tickets well in advance, as the prices pretty much always increase
- Consider flights to BWI
- Support the S-Line project!
I would consider a hotel credit card instead of the AGR card: your hotel stays are on your dime, and hotel prices in DC are generally high and fluctuate widely. Since I live in DC, I haven't thought much about which program has particularly great value, but generally the smaller ones are better values (i.e., don't do Hilton or Marriott). A Fed friend of mine is doing a similar arrangement and uses Choice hotels, since there are a few of their nicer Cambria hotels within DC.
When it's all said and done, you can then use your Amtrak + hotel points to treat the family to a rail-sleeper vacation to Florida or New Orleans --
Amtrak's southbound sleepers travel through NC in the late PM.