You haven't said where you are staying. If you are staying at any of the Monorail resorts or the Epcot resorts, park hopper could come in handy. When we stayed at Poly, we used the park hopper to drop by MK at the end of the day touring another park to catch the fireworks or ride BTMRR or get a dole whip float. When we stayed at BWI, we used the park hopper a lot with Epcot- dining in WS numerous times and also at times we'd walk through Epcot and monorail to MK. Yes, that takes more time to get to MK than the busses, but we avoid the busses if at all possible. Plus, that way I got many many stops for some Inca Kola at Clubcool.
When we went in July which obviously is busier than November, we did use the park hopper to get out of MK on Thursday. Touringplans had recommended MK that day, and we respectfully disagreed once arriving and seeing that everyone else had followed TPs advice. We went to another park (I think Epcot, but that was 4 years ago).
On our last trip, we used park hopper to do a "4 parks 1 world" day. That was a lot of fun! We started at DHS AM-EMH, followed by AK, then a rest at the hotel, then afternoon at Epcot, and winding down the day with Wishes and MSEP at MK. Your boys are probably old enough to do all of that, if you have a day to spare.
Like Mesaboy2 said, you can add park hopper at any point in your trip if you decide you want to do it, but it's the same cost whether you add it now, your first day of your trip, or your last day of your trip.
Have a great trip!