I agree with Camcolt's summary of Paradise Pier! We have stayed there twice (September of 04 and 05) and had wonderful stays both times. I highly recommend the theme park view, it was an additional $23 a night and well worth it for us. There is no counter service but there are some quick options in Downtown Disney which is a short walk and also if you are spending most of your time in
Disneyland and California Adventure you will probably eat there most of the time anyway. I know some people don't care for this hotel but we have enjoyed both of our stays there. If it can save you money over the Disneyland Hotel I think it is a great option for staying onsite. If however, the Disneyland Hotel is about the same or only a little more I do prefer that because I like their pool better and there are more dining options. One nice thing about Paradise Pier and the DLH is the nice, large rooms. They also have very comfortable daybeds at Paradise Pier. A couch that makes into something almost like a rollaway. Much easier to pull out than a sofabed but more comfortable than the daybeds at the Disneyland Hotel. The pool is not too themed but it does have a fantastic slide sort of the like the one at Boardwalk without the clown face. The pool area is nice with plenty of chairs but the pool itself is just a square pool. They also have a kiddie pool and a hot tub. They have a pool bar but it must only be open during peak season because for both of our September stays it was closed. So if you like to enjoy some kind of drink by the pool, bring your own!
The onsite hotels at Disneyland are not as themed at the WDW ones but I still prefer staying onsite, especially if I can get a good rate. I find both the DLH and PP somewhere between a moderate and a deluxe. They have the interior corridors, room service dining options and concierge options of a WDW deluxe but are not quite as "themed". Also, just so you will know, there are no buses to the parks because everything is walking distance (10-15 minutes) via DTD. There is the monorail stop in DTD that is maybe a 5 minute walk from both of those hotels that will take you straight into Tomorrowland.
I have not ever done the dining plan at Disneyland, I have heard its not that great of a deal. There are not as many sit down options but I find the counter selections more unique and varied than what they have at WDW. Our two must do's for sit downs each trip are Goofy's Kitchen (think Chef Mickey's) in the Disneyland Hotel and Blue Bayou which in Disneyland inside the Pirates of the Caribbean ride. You can make ps' 60 days out for either of those.
Have fun with your Disneyland planning!
P.S. 4 Days should be just about right. You can take it a good pace but probably see everything, especially given your WDW knowledge.