Recommendation: FSDO Reno
Got my EASA PPL-A validated to a FAA PPL this summer in Reno (We were going on vacation to Lake Tahoe, anyways). You need up to a 3 month wait to get the paperwork back from the FAA. After you receive the confirmation you have 6 months to get the license validated. You have to specify the FSDO in the application; go to that FSDO in the States, they compare their information with the reply you received and Bob's your uncle, you are good to go. The "hour" interview is only to see if you can speak english. At FSDO Reno, no flight was required since if your current EASA license is valid AND the FAA PPL is based on it, then logically you do not need to do a flight to prove you can fly. This is the policy in Reno; I have read that in Florida that they require a check flight. Yes, you can use this Adam guy to do the same, but if time allows I would definitely recommend taking 2 weeks and go to the States to do this. I can only say positive things about Mark at FSDO Reno and how great made the experience. AND flying around Reno in the desert just made the trip and the expenses worthwhile.
If you want to use your US licence outside of the States, you also require a FCC license. This can be obtained online and costs 60USD.
And no, there is no "easy" way to get your EASA ATPL converted to a FAA ATPL without tests, classroom, etc.