San Diego to Disneyland is a pretty easy drive - it's about 90 miles. Without traffic it'll take about 90 minutes, with (normal) traffic 2 - 2 1/2 hours. Depends on time of day and day of the week.
But you can also take the train from downtown San Diego to Anaheim and avoid the drive completely, and it's a nice trip on the train with no traffic to deal with!
we did this in June flew in took the bus down to the Amtrak station , took the train up the coast and a cab to the Candy Cane Inn stayed for 3 days, then back to San Diego for another 5 great days!! have fun!!!
We just drove from Anaheim to San Diego. It was an easy drive right down I5. We got off in the Newport Beach area though and drove the Pacific Highway until Dana Point and then got back on I5. It was easy and a very nice drive as we got to drive by Newport Beach, Laguana Beach and very scenic.