Transportation options:
Driving: I'm in Phoenix and it's about 700 miles round trip to
Disneyland...Gilbert is a bit more east than we are, but not by much. My car gets about 30mpg, so it's about 23 gallons of gas. Here in Arizona gas is about $2.60 a gallon, but in LA it's closer to $2.80....so if you budget $3 a gallon so you have a little extra to drive around town, you're looking at roughly $70 in gas. Driving takes about 6 hours each way.
Airplane: I only looked at Southwest, but there are quite a few flights that are around $109 to get to LA, but coming home there are a lot of $59 flights. So, unless you do some hunting on other airlines and come up with better prices....driving is cheaper even for just one person.
Hotels...I didn't hunt for deals/coupons, etc, so you might do better if you put some time in looking, but with taxes you're probably looking at $100+ a night for the hotels you listed.
Tickets: Again, I didn't go hunting for deals....just looked at Disney's website....3 day hopper is $186; 4 day hopper is $201. Buy these online as they are more expensive at the gate.
So....your budget would look like this:
Gas for driving $70
Hotel 2 nights $200
3 day hopper $186
Food at Disney $144
Total $600
Of course this is bare bones....no souveniors or other extras, but it could still be a very fun trip....after all you're at Disney!
Now...if you're willing to stay somewhere else, you could probably add a day or two. We'll be staying at the Extended Stay America for $65 a night for 3 people....so in your case you'd be able to stay 3 nights for around the same as your 2 nights....and of course a 4 day hopper is only $201, so you'd only be slightly over your budget but have another full day at Disneyland. If you're never done Disneyland before, 3 days would be my minimum, 4 would be better to do almost everything. Of course, I've never gone alone, so it might be easier to get more done without someone else wanting to go in another direction, lol.
EDITED: I see an above poster talked about the parking.....we walk from Extended Stay, it's not too bad for an adult....not sure I'd do it with little kids that will want/need to be carried on the walk home...and yeah, occasionally we stay just a little too long at the park and that walk home feels really long....but the times we went before we did APs, it was doable.
Another thing to consider.....do you think you'd do another similiar trip in the next 12 months? If you're able to afford it, an AP is only $428 (the deluxe plus parking), about double what you're paying now.....but then you only have gas, hotel and food to consider for future visits. It means coming up with some extra to make this trip happen with the AP cost, but then you could do long weekends at Disney! Take a friend next time and split the cost of gas and hotel and it's even better!