Lancaster breweries:
Wacker Brewery -Thistlefinch distillery is connected to them if you like spirits
Lancaster Brewing Co., not the best beers but a cool place with awesome food
Springhouse Taproom, it's the pub for all their beers
Short distance:
St. Boniface about 20 minutes away in Ephrata
Liquid Hero in York about 30 minutes (They have some decent IPAs)
Troegs is about 40 mintures (Im not a fan of their beers but the food is awesome)
Pizzaboy 45-50 minutes (if you drive like a NY'er, probably the only notable brewery to travel out of the city for)
Federal taphouse has about 100 beers on tap & i'd head to the Fridge too, best bottle shop in the city (they offer drafts and growler fills with a designated tap for Tired hands). Remember that Pa beer distro is a lot different than most states so if you want anything less of a case for take home you have to stick to certain shops. The city is pretty cool, have fun!