How easy is it for you to gain?

And I'm on the other end of the spectrum. 5ft tall and down to 100lbs!!  I wanted to stop around 120-130, but it doesn't seem to be up to me.  I TRY to eat, but I feel like I'm eating ALL day long.  I know I'm not because today I've had a slimfast shake and that's about it. 

Somehow I've got to find something I can eat that actually sticks to my bones!

I gain easily when I'm off track and eating the wrong foods. I also lose easily when I'm on track and eating all the right foods. I can eat 1500-1800cal daily and maintain well, but I also try to keep up a pretty good workout schedule so my caloric intake might be higher than others. If I get off track with my exercise I will notice a gain as well. I guess keeping the healthy lifestyle going for the long haul is most important, although difficult at times!

I am 3 1/2 years out and I haven't seen much problem with gaining. I went under goal and then worked on gaining a couple pounds to my goal.
I can eat mostly normal meals, but I limit simple carbs to small amounts. I eat lower carb veggies and proteins limited only by what my stomach can hold. I beleive I can easily gain weight if I eat too much bread, rice and potatoes. I eat them, just keeping the portions small.
I'm not sure if others have a big problem with weight gain or not.