Hi Ray - From downtown Holliston the closest train station is downtown Framingham (about a 10 minute drive). Here's the train schedule: MBTA Commuter Rail > Framingham / Worcester Lines Schedules and Maps
Driving would take about 45-60 minutes, depending on traffic. Sometimes it's a breeze, other times it's dreadful.
Summers are nice. We usually have a week or so with uncomfortable humidity when you really need A/C. This past summer was lovely though. Winters are long. Sometimes we get more snow than others but by the time late Feb rolls around most people are more than ready for spring. I'd definately say finding a place with a garage makes a huge difference in tolerating the snow! :-) And having good access to public transit!