Hi, thanks for the question.

Getting rid of moles can be a challenge but there is a lot of agreement that trapping is the most effective method.  Check out the following links:

Mole - Integrated Pest Management (msu.edu)

FS025: Mole Management in Turf and Gardens (Rutgers NJAES)

Moles (psu.edu)

Effective Mole Control (osu.edu)

As far as crabgrass, applying a crabgrass preemergent at the appropriate time in spring is the most efficient method of preventing crabgrass.  The GDD tracker can help with timing. a Thick healthy law will also help. Mowing high, fertilizing, properly, and seeding thin spots will also help. There are also post emergent herbicides can help control the crabgrass once it has started growing.  Check out the following links for more details.

GDD Tracker 4.0 - Turf Pest Management Tracking and Alerts with Growing Degree Day
 Models for Michigan, Illinois, Indiana and Ohio - Project initiated by Michigan State University (msu.edu)

Crabgrass | UMN Extension

I hope this is helpful.