IMO and the way we look at WDW trips right now with kids similar in ages to the OP is that this trip is about them, not you (not to insinuate anything about the OP).
In most parks, you can do the kid friendly rides that would give them max enjoyment in a few hours, and then gauge their stamina and decide to take breaks as needed. Don't schedule too many ADRs in the mid day so you have the flexibility.
My wife and I realize that the days of riding Space Mountain over and over again are coming, just not now. This leave us time to give the kids the most time to ride their attractions. If we do need a thrill, we look for attractions with single rider lines while the other takes the kids for some ice cream.
I recommend character dining because IMO, it knocks out 2 birds with one stone—eating, and having interactions with the characters. With the way WDW now houses most of their main char in areas with long lines, having Char meals saves that park time.
As for parks, I would invest in a park hopper tix and try to get to the other 3 parks (EP, DS and AK) in the AM and then MK at afternoon/night. Given your resort choice (excellent choice BTW, we stay at BLT for this exact reason—convenience), getting back to the park after mid day breaks is a quick skip. Sometimes, a longer trip back from a park in mid day is good b/c the kids may fall asleep on the bus back instead of trying to calm them down in the resort room. Likewise, at the end of the day, when they are at their most tired and cranky, returning to the resort is the shortest it can be vs waiting for bus after bus. The only exception would be for EP where you can grab the monorail back.
You may want to look into some special items like Wishes Desert party at MK. Yes it is an extra expense, but it will give you and your kids an A+, less crowded place to watch fireworks—sometimes, tight crowds at fireworks time can make kids more antsy. And being it is a secluded, special ticket event, it will give you some extra time to hit attractions vs wasting time staking out a good spot—IMO, Its all about maximizing your park time.
Reality is, go with the flow, read your kids stamina and patience and be prepared to change plans on a dime. You may not do everything, but what you do get to enjoy together will be magical.
Have A Blast!!!!
Edit:
Just re-read you post (should have done that more carefully before my rant), Seems the OP is ok with not seeing everything, which I think is a good attitude. OP also said its thier first trip. As a family or overall? If it is your 1st trip to the World, beware, it can be very overwhelming once you get there. While now you may be saying you may not need a break, but once there you may find it needed. Plus, A LOT depends on when you are going. I didn't see that in the original post. I really think that is the #1 factor. We go mid summer, so a break is not only recommended, but actually a must. plus the parks are open later, so we can go back when the heat breaks. If you age going off season, and its not so hot/crowded, then you may get by with the stroller nap and ice cream on a bench.