If you are considering LI, a 50 minute (or so) commute to Penn Station means that you can consider towns as far east as Massapequa on the south shore, and Syosset on the north shore. I took a look at what is available in our MLS system, and there are 436 colonials available that match your general criteria. I suggest that you get a good LI map and follow the train tracks to see the towns that border them and make note of the towns. Talk to family and friends, or co-workers for recommendations about school districts, etc. Once you have a few preferred locations in mind, get in touch with a good agent to help you with getting out to see some homes. Consider using a buyer's agent who will work in your best interests, not the seller's.
Good luck with your search and make the most of the wide choice in homes available today.