My DS4 is about 41-42" now and is eager to ride the roller coasters. He’ll be close to 5 when we have our trip. I’m thinking of planning a day at the MK with a roller coaster progression to see what he is up to. Here’s my thoughts on the order.
Barnstormer
7DMT
BTMR
Space Mountain (if he’s 44" by then)
What do you think?
That’s perfect order for intensity
I agree that’s the perfect order for progressing intensity. My DS4 and DD7 only made it to 7DMT before calling uncle. 
We took our son to Disney 2 weeks after his 4th birthday in April of last year. He didn’t like 7DMT all that much. He said he bumped his head. He did, however love, I mean love Thunder Mountain. I bet we rode it 15 or 16 times. Space Mountain is too dark and not being able to sit next to someone made it a hard no from him for our upcoming trip even if he’s tall enough (he won’t be). He’s 43.5 inches now with 2 weeks until our trip. He really wants to ride EE at AK. He also absolutely loves Test Track
That’s the order I would recommend. Definitely do all of the MK coasters before progressing to RnRC or EE.
DD5 and I both found Barnstormer very jerky and unpleasant. If I was judging roller coasters by it we wouldn’t have even tried 7DMT, which we did enjoy.
Interesting. Thanks for pointing out that it’s not necessarily linear. We have been telling DS4 for months now that he needs to eat all his dinner so he can grow and ride more rides at WDW. As a fall back position he has coarse curly hair and is refusing to cut it. We could alway pick it out if he needs that extra inch.
I agree. I’m not even sure my DS7 is up to RnRC or EE.
He was able to go on Barnstormer when he was almost 3 and loved it. He’s really chomping at the bit to get to the other coasters.
Be interesting to see which of the bigger coasters becomes his favorite. Hope they live up to his expectations.
I like the order of progression. We did something similar on our one MK day in August. I FPP 7D around noon, Splash (which was is not a roller coaster, but was making mine nervous, too) around 1, and Space around 5 PM (BTMR was closed for our trip). We rode the Barnstormer standby several times in the morning. DS8 didn’t love Space, but he did it, and I don’t think he would have if he didn’t have those others under his belt.
2 days later he rode RnR and loved it!
At AK, I recommend a few rides on Primeval Whirl before venturing to Everest (even if it means longer lines).
I had to laugh about the hair. 
When DS was 6, he was almost 48 in, and we didn’t cut his hair for months in anticipation of a trip to Busch Gardens!
Have fun!
I am sure you’re kidding. I wouldn’t monkey with the height requirements. My wife recommended something similar for our DS4 (almost 5), but quickly changed course when I said, “you’ll feel really guilty if we fudged the heights and he got hurt.”
My nephew was tall enough for Everest before he was tall enough for Primeval. You might not have that option.
I am kidding about fudging the requirements with bigger hair. I am not kidding about using it as an incentive to get him to eat his dinner.
I am with NoCapes. My kids hated the Barnstomer - too jerky. BTMR is actually easier to ride and more comfortable.
Fully 100% support!
Last night he asked me if he looked taller as he finished cleaning his plate. This is a hard-won and infrequent parental success!
We heavily encouraged our 7 year old onto Space first (as we wanted to do it). She reluctantly did it but then found out she was a speed junky. So we ended up skipping barn stormer. None of us liked 7D (I don’t get it). But think that is a great progression of intensity. However if you don’t get FP for 7D - I may do that first so your 5 yr old isn’t 7 by the time you get through the line.
7d HAS to be more about the theming than the ride itself. Also, I hope you saw the video they create for you.
Hi- HOOOOOOOOOOOOOOO!
I would agree. It’s very much about the theming.