Which of these hotels in Carlsbad would be best for an overnight stay: Grand Pacific Palisades? Holiday Inn Carlsbad? Fairfield Inn? Pelican Cove Inn? Recomendations would be appreciated.

Mrs. D., I am not familiar with any of these hotels, but I thought you might be interested to know that you can stay in San Diego and easily make the drive to Legoland for the day. We did that last year and it was no problem, maybe a 45 minute drive at the most. Also, this summer we will stay in Laguna Beach (north) and drive to Legoland for the day and I don't anticipate more than a 40 minute drive, outside of rush hour traffic. I thought I'd mention this, since you might be planning a stay somewhere else in Southern California and so you know you don't have to stay right near the park. Have fun! My kids love Legoland, I bet yours will too.

Your best choice would be the Holiday Inn off Palamar Road. It's only a few blocks from Legoland. This Hotel is unique as it has a windmill on up of it and ocean views... Artists come from all over the world to paint it in spring when the flower fields directly acress the street are in is also onsite. And my favorative Islands Restuarant acoross the street.

Thanks for your helpful responses! Any other recommendations would be appreciated.

If choosing the holiday inn, see if you can get the "50th anniversary special rates" advertised on the holiday inns website.

Also you might want to look into the Best Western Beach Terrace.

I have stayed at the Grand Pacific Palisades and it is nice. Its restaurant is a Karl Strauss Brewery restaurant, and it is good and reasonably priced. The Grand Pacific is slightly closer to Legoland but both it and the Holiday Inn are very close to Legoland.
The Holiday Inn has a TGIFriday's attached. Right across the street is an OK outlet mall, if you are into shopping.
Carlsbad also has a 1.5 year old Hilton that is just a little farther from Legoland than the other two hotels, but still very close.