Here's a breakdown of each team's schedule.
No common opponents.
WSU has played 1 FBS and 0 Non-D1. Maine has played 2 FBS and 0 Non-D1. Opponent's overall combined record is 66-71 (.482) for WSU, and 57-78 (.422) for Maine. SOS edge goes to WSU.
WSU is 6-0 in Home games. Weber's six Home wins were against S Dakota (4-7), N Colorado (2-9), E Wash (10-2), Montana St (8-5), Sac St (2-8), and SEMO (9-4). Those teams are a combined 35-35 (.500). Average score in wins and all Home games was 32-18. E Wash, Montana St, and SEMO were playoff teams.
Maine is 4-3 in Away games. Maine's four Away wins were against FBS W Kentucky (3-9), Rhode Island (6-5), Towson (7-5), and Richmond (4-7). Those teams are a combined 20-26 (.435). Average score in Away wins was 33-25. Away losses were to FBS C Michigan (1-11), Yale (5-5), and William & Mary (4-6). Those teams are a combined 10-22 (.313). Average score in Away losses was 13-26. Overall combined record of all teams played Away is 30-48 (.385). Average score in all Away games was 24-26. Only Towson was a playoff team.
It's also worth noting that although Maine won the CAA outright, going 7-1, they didn't play 3 of the next best 4 teams (JMU 6-2, Delaware 5-3, and Stony Brook 5-3). And the CAA has gone 2-5 in the playoffs.
Based on records and average scores Weber should be the favorite, with the score being something like 29-21. Latest 5Dimes line has WSU -7, O/U 48.5.