These threads from this sticky (
* DLR Info/Links - Maps, Hotels, DISer Reviews, Hydroguy's tips, NEWBIE INFO here!) at the top of the first page will have lots of great information for you:
A DLR Guide for WDW Vets -- a classic thread! Pre-SWGE, but still very helpful.
Detailed Weather Data for DLR -- reliably warmest months will be July through October
"Comparison of Weather For WDW and DLR"
www.disboards.com/showthread.php?t=1711098 -- for reference
"Understanding AP Blockouts and Impact on Crowds"
www.disboards.com/showthread.php?t=2365983 -- this has a huge impact on crowds at DLR -- always check that AP Blockout Calendar!
"Choosing the Right DLR Area Hotel for You"
www.disboards.com/threads/choosing-the-right-hotel-for-you.3656512/-- On site and off site have pros and cons at DLR -- on site at DLR is not the same as it is at WDW and off site is not the same, either.
2019 Calendar of Events & School Breaks and DLR -- this will give you some idea of where the major school breaks fall. NB that Southern CA has traditional, year round, and home school calendars. And that the districts that affect DLR the most come from CA (Southern and Northern), OR, WA, AZ, NV, and
UT -- that's a LOT of school districts!
Do you like Halloween? Halloween Time is busy, but a super fun time in the parks. Holiday Time at Christmas is also a wonderful time to visit.
It's better for a first visit to aim for a peak time (vs. a non-peak time) -- you'll get longer hours, more staffing, more entertainment, nighttime entertainment every night (instead of weekends only), fewer refurbs, rides running at full capacity, etc. When the parks are ready to handle the crowds, things run very smoothly and you don't feel the crowds so much.
We tell everyone here: don't try to second guess the crowds at DLR -- it's complicated and not always a winning game -- choose the time that works best for you, then come back here to double check that nothing crazy will be going on at the same time. With good planning and a positive attitude, even the busiest time can be a magical time at DLR!