Thanks folks -- this has been helpful. Does anyone know how the FP+ works if you do a split stay? Can I book FP+ 60 days out for just the days we are on property or for our whole trip? Also, maybe a silly question -- but as long as we use all the tickets within 14 days, we can do like 2 days at the parks, 1 day off, and then go back -- essentially, I would like to break up our last few days in the park. I can do that, right? I feel like I had to do less research to write my final thesis for college, than prepping for a Disney trip! LOL!
You can book FP+ for the days you will be onsite (including arrival and check out day) at 60 days and would have to wait until 30 days to book the rest.
Yes, you are correct, you do not have to use the tickets on consecutive days. You can do 3 days, take two days off, and then do another 3 days.
As for the onsite/offsite advice... We always choose to stay on site. We do make use of the EMHs, we love to use the Disney transportation, and we feel it gives us the most flexibility (we always get Park hoppers and occasionally like to split up).
It really depends on your family and your priorities. For many the extra space you can get offsite is worth more than anything. My family has plenty of personal space year round and we get along well, so we do not mind having the five of us sharing one room at Disney (and we usually go for 10-14 days).
We think the morning EMHs are a huge benefit. A few years ago they were offered every day and when my kids were younger we attended EMH every single morning. Some like to sleep in or don't have park hoppers, so this isn't a benefit they choose to take advantage of.
Staying onsite also gives us flexibility with transportation. Although we stay together most of the time, it's nice to have options. For example, my oldest and I had a mother-daughter tradition of a late night at MK our first few trips. Once DS got sick, so DH took him back to the room. Now my kids are older, so maybe they want to hop to a different park while DH and I go back to the resort. If we were staying offsite we wouldn't have the option of going two places at one time since we only have one vehicle.