Albeit not insurmountable, 20K BIS miles on AS in a month is a monumental task. Let's shrink a month into two 3-day, 2-night itineraries. Each itinerary has a red-eye and an open jaw. BOS-JFK on one and a short surface sector from MIA to FLL on the other.

An AS booked AA award or revenue AA flight BOS-JFK would be required; either evening of Jan 14th or morning of the 15th. Either will earn EQM, but they won’t apply towards your challenge.
6 flights. Total EQM 11,905
Surface sector from MIA to FLL.
5 flights. Total EQM 9,976
Itineraries: 2
Total fare: 1288.29
Flights: 11
Price per flight: $117.12
Miles flown: 21,881
Average flight length: 1,989
CPM 5.89
RDM 75K : 49,232
RDM 100K 54,702
I tried to keep it as close to the weekends as possible, however some routes are cheapest mid-week, some are random, some include a Saturday, but significantly higher on Friday & Monday, and some routes are discounted everyday. The open-jaw to JFK picks up a cheaper fare and SFO into BUR saves another overnight. Similarly, the open-jaw MIA to FLL effects the same back to LAX.
Some interesting facts:- As the crow flies, LAX is closer to HNL than it is to Boston
- SFO is closer to HNL than it is to JFK
- Reno, NV is farther West than Los Angeles, CA
- ANC is the closest US Westcoast city to FRA
- All the Westcoast major cities from YVR to SAN are ~equidistant between TYO & LHR.
- AS now has nonstop service JFK-PVR; PVR is closer to JFK than it is to SEA.
- MIA-LIR is ~ the same distance as SEA-PHX.
- SEA is closer to CUN than it is to MIA.
James