American expat who has spent over 10 years in Europe in the UK and Germany. With family all over the US from Hawaii to Boulder to Washington DC.
Terminal 2 has long customs lines for non-EU passports, so it might be cutting it very close to make your train. I would recommend spending the extra $$ to take the Heathrow Express train to London Paddington (15 minutes) and then catching the Hammersmith&City or... See More
You might try the Arlington area on the Virginia side of things. Towns like Clarendon and Rosslyn are just a few stops on the Orange line into DC and will be considerably cheaper. Could also try Alexandria (Virginia)... See More