Just one point to underscore since I think things may be a little confusing. If you are going to use the arrivals lounge in T5 (upstairs after you get out of passport control and baggage claim--just follow the signs), to get to T2 you need to take either the Tube or the Heathrow Express. These have different platforms in the basements of T5 if I recall (I've only taken the Heathrow Express) so you need to make a decision as to which you will take before you find the floor/platform. The Tube only takes contactless credit cards which are fairly rare in the US. I don't have one and I have half a dozen credit cards. You can also purchase a ticket. The Heathrow Express doesn't cost anything if you are getting off at T2/T3 (same stop) although they are always selling tickets to central London. If they stop you and ask you to purchase a ticket, just tell them you are transferring to T2. T2/T3 is one stop (about five minutes) and then you will follow the signs to T2. It's not as complicated as it sounds, but the first time you do it you will be a little unsure or nervous and that's normal. But everything should be fine.