Hi Melissa.
I am no 'expert' when it comes to crowd patterns at Disneyland during Spring Break, but i have visited in April and have done research into that time period that might help a little.
I usually avoid Spring Break periods when i can , as it can get crazy. Not just crowd levels, but the young crowd - teens and college age folks.
I learned the hard way one year in Florida when i went down to visit WDW during my birthday in mid-March.
Egad...never again !
I visited Disneyland last April, during the last week. It was busier then i was expecting, but not so busy it effected you in a bad way.
The weeks before i had read ahead of time as being busier as Easter was very late last year and always effects crowd levels.
The general rule i have observed is that one should stay away during the two weeks leading up to Easter, and the two weeks afterwards.
So mid March through mid April is the main 'Spring Break' period when crowd levels may be up there.
Looking at your dates, it looks like you would be there during that busy period.
As far as 'cheap hotels' goes...i have two that i have good luck with that are both about a 5 to 10 minute walk to the front gates of the Parks.
The Quality Inn & Suites on Katella Ave, or the Stay America Suites on S. Clementine.
Most visitors want to stay at the many hotels lined up across the street from the Parks on Harbor Blvd., so those are options you may want to look into as well if that interests you.
I personally like my two picks as they are far enough removed from the busy 'tourist scene' that is on Harbor, but still close enough to the Parks to easily walk to.
Quality is a small motel, but nice for what it is.
I like it a lot, and usually stay here when in town. Fits my simple needs like a glove.
Full free breakfast in the morning is included, plus the usual hotel amenities.
They have two sizes of clean rooms with very comfy beds, and a friendly staff.
Rooms range from $69 to $112 depending on the season, but for April the last time i looked two weeks ago they were $81 a night.
The motel is located in a nice palm tree lined area within sight of DCA and is a short walk to DTD.
Stay America Suites is a hotel that has a 'apartment complex' feel to it.
It is a high rise hotel next door to a local shopping and dining complex called the Anaheim Gardenwalk.
All of it's rooms are suites that include a small full kitchen, and they have several room sizes to choose from.
The longer you stay, the less you pay per night, so if you are staying a week or more this may be a better price option then the Quality Inn.
Average is $69 to $89 off season ( week long stay rate )...slightly more possible during peak times.
Hope this helps you out some !
