Our experience last August suggests to me that you may find that two nights is too brief for Universal, even if you stay on-site.
We did two nights at Universal in August. It was supposed to be four nights but a dental emergency for my daughter turned the first week of our vacation into chaos (but that is a different story). After Universal, we did seven nights at WL, as scheduled. I can say with certainty that next time Universal will get a larger share of our time. The child we brought is only seven (our daughter). With two teenage boys, you may want to give Universal some more time. (Our other three children, now grown, were boys. I suspect that when they were teens, Unversal would have been a big favorite over WDW.)
At WDW, we loved the WL and we used FastPass a lot and got most of WDW done using a "back to the resort for mid-day breaks" stragegy. But nothing is as good as the Universal FOTL for on-site guests. In hindsight, we figured out that the room key lets you do the park in any order you like, because the lines and crowds become irrelevant. In essence, you can just circle the park. With this in mind, it suggests using the "second part" of each day to do other things and use the mornings to best effect in the two Universal parks.
Noitce, I did not get into a discussion of which parks are "better", whatever that means. We found that both Universal and WDW give you value and a terrific experience. But there are differences and there are numerous discussions of that on these Boards. We found IOA's attractions more keyed to older kids (note for those two boys) and USF is much bigger geographically than MGM.
As for walking from the HRH to the parks, the marked path is to the right of the pool slide. HOWEVER, there is a gate at the left end of the hotel (as you look at the pool) and that leads to a path that goes straight along the canal (which the launches travel in). Indeed, the hotel has interior stairways that end at this path, too, so that can shorten the interior walk, also.
We walked when the launch was not visible at the CW dock and rode the launch when it was there. Both are pretty and easy.
As for breakfast, both IOA and USF have quick stop table service type resaurants for breakfast just inside the gates. Both have the usual croissant sandwich breakfasts or cereals and several mega-carolie pastries. The one in USF is to the right on the main street as you enter and the one in IOA is in the Port of Entry area, also on the right. (Sorry, the names escape me.) Since both parks have early entry days for on-site guests, we used these days and the two restaurants I just described for breakfasts.
For dinner, Mythos was great and I recommend it. The Sunset Grill was fine but nothing to seek out. I have eaten at six or seven different sites of The Palm (include the two in NYC) but not the one at HRH. Generally, the Palm's food is great, the portions are large and the prices are high. It is a "power meal" environment.
By way of a tangential suggestion (if you are concerned that the boys won't become fixated by the two Universal parks), consider more time at Universal and a car rental. That would allow for splitting days and doing Sea World (or GatorLand--a campy place that might amuse your boys) after a mid-day break from the Universal parks. Also, it permits you to find other places for dinner, off-site. (Check the UG's off-site recommendations, along with those on the DIS).
Have fun next August.