You may already know this, but after a few more hours sifting through regulations while reading the Airman Certification Standards for UAS I noticed reference AC 107-2. I looked it up and found:
CHAPTER 4. PART 107 SUBPART A, GENERAL 4.1 Applicability. This chapter provides guidance regarding the applicability of part 107 to civil small UA operations conducted within the NAS. However, part 107 does NOT apply to the following: 1. Model aircraft that are operated in accordance with Part 101 Subpart E, Model Aircraft
Then I noticed that if operating under Part 101 (sub 250g, recreational use) there are NO airspace class restrictions. It simply states:
(e) When flown within 5 miles of an airport, the operator of the aircraft provides the airport operator and the airport air traffic control tower (when an air traffic facility is located at the airport) with prior notice of the operation.
Which is different than Part 107 which requires "prior authorization". You don't need "authorization" under part 101, you are simply required to NOTIFY them. Just to be sure, I checked the applicability of Part 107 as defined within itself:
107.1 Applicability.
(a) Except as provided in paragraph (b) of this section, this part applies to the registration, airman certification, and operation of civil small unmanned aircraft systems within the United States.
(b) This part does not apply to the following:
(1) Air carrier operations;
(2) Any aircraft subject to the provisions of part 101 of this chapter
Part 107 regulations do NOT apply to aircraft operated under Part 101, meaning you can fly them wherever you want as long as you NOTIFY any ATC within 5 miles, and fly within "community based" (AMA) safety guidelines. There is also no 400ft operating ceiling under Part 101, but the AMA Safety Handbook imposes a 400 foot ceiling within 3 miles of an airport.
References: FAR subchapter F, FAA-S-ACS-10A (UAS Airman Certification Standards), Advisory Circular AC 107-2
I have read a lot of conflicting/incorrect information on multiple forums so please do what I did and check the references for yourself, and let me know if I missed anything!