I took a quick look at the online pdf timetable.
Below is the breakdown of flights from LGA this summer. FPO is the only Saturday beyond-perimeter flight operating right now. Besides that, only CLT and PIT see mainline during the week other than Shuttle. PHL gets a 319 on Saturday only.
Weekday Departures (weekend schedules and aircraft changes not included)
ALB: 4 x DH8
BWI: 8 - 7x DH8, 1 x ERJ on Friday only
BGR: 4 - 2x CRJ, 2x DH8
BOS: 16 x 319
BUF: 10 - 6x DH8, 4x CRJ
BTV: 7 x DH8
CHS: 2 x CRJ
CLT: 11 - 8 Mainline 3x 321, 4x 319, 1x 734 (only US 737 into LGA!) 3 Express 1x CR7, 2x CRJ
CHO: 3 x SF3
CMH: 6 - 2x E70, 2x ERJ, 2x CRJ
DAY: 4 - 3x CRJ, 1x ERJ
GSO: 6 - 4x ERJ, 2x CRJ
HYA: 2 x SF3
IND: 6 - 3x CRJ, 2x ERJ, 1x E70
ITH: 3x DH8
SDF: 3 - 2x ERJ, 1x CRJ
MHT: 4 x SF3
MVY: 4 x SF3
ACK: 4 x SF3
ORF: 7 - 4x CRJ, 3x DH8
PHL: 12 - 8x DH8, 3x CRJ, 1x E70
PIT: 9- 1x 319, 3x E70, 2x E75, 2x CRJ, 1x ERJ
PWM: 6x CRJ
PVD: 4x DH8
RDU: 8 - 7x CRJ, 1x ERJ
RIC: 7 - 4x CRJ, 1 x E70, 1x DH8, 1x ERJ
ROA: 3x DH8
ROC: 8 - 7x DH8, 1x CRJ
SAV: 1x E70
SYR: 9x DH8
DCA: 16 x 319
ILM: 3 - 2xERJ, 1x CRJ
Which gates do the E Jets use, Express or Mainline? 9 non-shuttle main line flights!