No... you do not want to charge to 100% as you won't have any re-gen braking (because there will be no place to put the energy into the batteries) for the first part of your trip (likely before you get to the highway). Plus since each 10% will give you roughly 25 miles or so of range, it is very unlikely, you'll need those last 25 miles to get to the any SC that you'll need to stop at. Charge to 90 or 95% the night before. Put your destination into the Navigation system (you can do this prior to the trip), and it'll tell you, what SCs you'll likely need to stop at. However, be aware that the actual planned stops may change as you are driving, mostly depending on your speed, and other factors (winds, traffic, etc) as the Navigation system figures out how the trip is going (plus how busy are the SCs). It will also allow the car to pre-condition the battery for faster charging. Best trip planning is to drive until the battery gets to roughly 10% (although some may prefer 15%-ish), charge up to 60-70% and get to the next SC. 10% to 50% is the fastest, then the charging rates starts to taper down. That will take 20-25 minutes, time to stretch your legs, let the dogs out, use the bathroom, get a bite to eat, wash the windshield (you did bring some towels and fluid along, didn't you?). The system will also tell you the % estimate charge that you are likely to arrive at the next SC.
Speed is the biggest decision that you'll make. Although the chart below is for a model 3, you can see what speed does to your range. 5 mph makes a difference. You can get 387 miles of range or 254... your choice.
Once you get close to the SC, you can press on the icon and see what kind of SC you are heading towards and how busy. It can also be a guessing game for the kids to get them actively involved (guess what type and how busy). Keep in mind (or maybe learn) that there at at least 3 different versions of SCs. V1 and V2 are all rated at 150 kWh or less. That also means that there are 2 SCs SHARED. If someone is in 1A, you don't want to park in 1B or the rate of recharge (for both of you) will be halved. If it is crowded, you may not have a choice. V3 chargers, 250kWh, are not shared, so you can park and charge at any charger without impacting you or others.
I agree with pre-planning with ABRP just to give you an idea of how many stops you will be taking, I prefer the classic interface.
ABRP
Another nice feature with ABRP, is that you can select different vehicles, and see how that would change the trip (and the costs). However, the actual costs will be higher as rates change quicker than the website can keep track of.
My guess is at least 6-8 stops for 1,200 miles (every 180 miles, if at highway speeds). If you are planning to make it a multi-day trip (as 1,200 miles in 1 day is tough), you may want to as see if there is a SC (or even a L2) at your stopover. Plug Share is another good site for that. Make sure to click of the proper power adapters that you have,
Plug Share
If you have a mobile charger with a 30A or 50A adapter, then you also have the option, if really needed, to see if an RV park will let you charge (for a price). It's a much slower L2, not SC, but it's an option. Keep in mind that there are TWO (2) types of 30A plugs, a TT-30 and a NEMA 14-30. One is for 120V and the other is 240V. Not sure which one RV parks usually use.