I could be wrong, but I highly doubt you would have any problems with noisy children since the kids will still be in school during your stay.
Haven't stayed at the Shoreway, but it gets similar reviews to most every other motel/hotel in Falmouth. Doesn't seem to be any complaints about the place being dirty, but I did see a few reviews about the decor being a bit dated. Once again, you'll get that with many of the Falmouth offerings.
One place I have stayed was the Holiday Inn Falmouth. Yes, it's a little off the beaten path for Main Street and the beaches (about a mile to Main and 2 to the beaches), but it just underwent a renovation 18 months ago, and the rooms were clean and well presented. Very friendly staff, indoor pool, free Green Mountain Coffee in the lobby, and the attached restaurant, KC Steakhouse served up some pretty good food. Room service was even surprisingly affordable, too.
There's a pretty pond across the street and the drive to Main Street is all of 3 minutes, and the beaches less then 10. It's really not walkable since the hotel sits on a very busy road that doesn't have sidewalks in certain areas.
I think you will be fine at Shoreway Acres, but if you decide to stay at the Holiday Inn instead, then let me know. I see it listed on Hotwire for those travel dates for $136/night, per room. Best rate showing on the hotels website is $158/night, so you would save yourself some $45/night for both rooms.
Edited: 9:12 pm, May 04, 2011