I’m new to the forum, and hope that you guys can help me. My family of five are not new to visiting Disney, but we’ve always gone in the month of June (heat, humidity, crowds). This year, instead of going in June, we are planning to try Disney and Universal in December during the Christmas season! We have used the Touring Plans before in June, and boy, what a difference they made! But since we will be staying offsite, will they be just as helpful during this busy time? We have never been to Universal, and I know that they have the Unlimited Express; should I invest? And does making the Fastpass+ reservations shake up the Touring Plans? I will be using the Lines App on my Samsung so that I can get up to date help, I appreciate any advice anyone could give. Thanks! And Happy New Year. 
I can’t speak from experience for Christmas season, but a liner used them last year during Christmas week and were able to get EVERYTHING they wanted done ad Disney.
So yes, regardless of where you’re staying, they’re worth it. The only advice I would give is: if you can, stay away from a park with EMH since you can’t take advantage of it, as that park will tend to be more crowded. Especially with morning EMH, you will be behind the wave, rather than leading it, since others will be in earlier than you can get in.
And welcome to the forums! Drop in on the daily threads and say hello. There are 2 - 1 clean and 1 a little more risque. They are in the La Cava section. If you can’t get in there yet, don’t worry - it’s nothing personal. I think it’s still set up that you have to post a few times over a few days simply to prevent robo-posting, so after 2-3 days it should be an option for you.
In the mean time, feel free to ask any questions you have. People here are very helpful, although activity can ebb and flow throughout the day.
Awesome! Thanks a lot! Wanted to make sure that the Lines App and the Touring Plans would still just as effective as before. I was truly impressed with the ease of which we toured the parks and we even got to ride the Rockin’ Roller Coaster at Hollywood Studios five times–no joke. I was totally sold on Lines after that little episode. And in the middle of summer! On an “8” day! Awesome.
Well, Christmas week is a different animal - more like a 15 on a scale of 1-10. However, with a good plan - and Rope Drop - it’s still doable. However, you might need to set expectations a little lower on what you accomplish, and remember to take in all the special holiday things.
Oh, BTW, the Universal side of the forums (and Chat) tends to be a little less populated, so feel free to post your questions here as well.
Oh, believe me, my expectations are quite low I assure you. 
I know that it will be a mad house, I just wanted to make sure we would still have a great time. Thanks for all your advice!
@GrumpyInBrooklyn was just there, if you want to search the posts about his trip. It may give you some ideas.
Looks like you have a double post here - check out my answer on your other post Do Touring Plans REALLY Work? - #3 by brklinck