We just left DL yesterday after 6 days there - the weather was gorgeous! 70s and low 80s every day - perfect for rides in the morning and pool break in the afternoon. Never rained. The mornings started off cool and overcast; by 10:00 the sun broke out and stayed out until 7:00 or so, when things cool off considerably. It is a bit humid in the mornings and evenings but nothing like FL! We've been once in June and three times in August - the weather definitely varies - we've had 70s and 90s. But it always cools off in the evening.
Crowds are not bad if you know how to avoid them! Up until 10:00 (11:00 at DCA) most lines are under 20 minutes. To ride Star Tours, TSMM, or Space Mountain without long lines, get there early or get a FP (no FP for TSMM, though). In the middle of the day the wait times for those attractions, as well as Splash Mountain and maybe Nemo (I am sure I am forgetting something) can be well over an hour. (Esp. ST - that can be 2 hours.) Get the big rides in early, then visit the attractions or the rides with shorter lines late morning, take a break midday and come back in the evening to use your FPs, and you will be fine! The big difference to me between crowded DL and crowded MK is that DL is smaller - it has narrower walkways and feels more crowded just walking around. You can literally come to a standstill trying to get out of Tomorrowland at times. We try to avoid the most crowded times of the day at DL. DCA (when not under construction with half the park closed like it is now) is fantastic - nice wide walkways, open spaces - just feels less crowded.
If you have an iPhone, download some of the wait time apps (just search for Disneyland wait times) and you can get an idea of what the wait times are like for different rides and at different times of the day.
P.S. Hot in Anaheim is nothing like hot in Orlando - the humidity makes it so much worse in Orlando, IMO. The sun is a little more brutal in CA but the it is almost always pleasant in the shade no matter how hot it gets.
I am eating my heart out at the weather you had. We were there a few days before you & had temps of 89 all 3 days, with humidity. The parks were very crowded IMO, however I still believe it was so much easier to accomplish so much more, even w/ little planning & parkhopping on a whim, than you can ever dream of at WDW.
Experienced WDW as a young child the 2nd year they were open & it has always had a piece of my heart. Visited DLR the first time just over 20 years ago & still adored WDW much more. Told DH the next Disney visit I think I want to go back to DLR, not WDW & not even my happy place the Poly.
One thing I do feel about DLR & crowds is the evenings get a little tense in both parks. WOC was amazing show & I would have gladly watched every night. The process of fastpass, line up in a herd to go to use your pass for your viewing area & then standing and waiting, particularly in the heat & humidity is grueling. Asked several CM's in DL, including Fantasmic people, about where & how to watch the show. Got great info, but people even 40 min. ahead of show were kind of herded along aggressively w/ little information about how to find a spot to watch. Because the park is so wonderfully landscaped, there are many trees obscuring castle view for the fireworks. Asked a Main Street CM directly, what are the rules for where you can watch? Basically the rules are the street, no walkways.
They are very rope-happy about setting up walking areas, which they've got to do for safety. It's annoying when you've followed the rules & then CM's direct latecomers, even during the show, under the ropes where you're standing, pushing you forward into the people who are less than an arm's length in front of you, who have less than an arm's length of room in front of them, etc., etc. People got very irritated w/ us because CM's were directing them into our space & we weren't moving because we had approximately five inches max we could move our feet forward. After fireworks walking in Tomorrowland is pandemonium, with CM's giving different directions of which way to walk through the area, even the same CM giving different directions to people walking through! I understand dealing w/ so many people is never going to be 100-percent smooth, but I'm sure there are some tweaks here & there which will help guests enjoy the experience much better.