Sold my 2010 Civic to get a truck, which was a mistake. Now selling a 2007 F-150 2WD (~$5k) and want to go back to a Civic for the MPG. Also considering a Subaru for AWD in PA snow. Is this a good plan?

Going back to a Civic makes sense if the main issue is fuel cost. A 4–5 mile daily commute in an F-150 is expensive no matter how you look at it.

Three options that fit a $5k budget:

Honda Civic. The 2013–2015 generation is the one to look for. Combined fuel economy runs 30–35 MPG, the car has a solid reliability record at high mileage, and a manual transmission opens up more choices at that price. For snow in PA, winter tires on steel wheels handle light to moderate snowfall well. A basic set costs around $300–500 to set up once, and you swap them twice a year.

Subaru Impreza. The 2012–2014 range fits the budget and has AWD standard. One thing to know: the 2.5L engine on the 2010 and 2011 models had a head gasket problem that Subaru corrected in 2012. Avoid those two years if you can. Fuel economy is around 28–30 MPG combined, which is worse than the Civic but still a significant improvement over the F-150.

Ford Escape Hybrid (2008–2012). AWD is available, city fuel economy is 30–34 MPG (higher than the Civic in stop-and-go traffic), and the hybrid system on this generation has held up well over long-term ownership. Less popular in searches than the other two, so used prices tend to be lower. More cargo space than either option above.

For a short daily commute in PA: the Civic with a winter tire setup is cheaper to buy and cheaper to run. The Impreza makes sense only if you would rather not swap tires twice a year.