Not sure which resources to use

I'm just looking for advice on resources to use for my daughter's education. She's 4--not reading yet or anything. She has really clear interests -- unfortunately her MAIN interest is in horses, and classes don't start until 5 years. There's a preschool horse program here, but it's 100/month -- too steep for us. She also enjoys yoga Saturday mornings and she might start ballet.

She's a very social girl, and really enjoys being around other kids. I've tried to help her meet other kids, but the other parents usually aren't responsive or their kids are very young (13 months, 2). We're also probably going to move pretty soon, so maybe opportunities wherever we go would be better ... who knows.

Anyway, I'm looking for ideas for things at home to help her. She really enjoys looking at books, especially flower fairies, horses, and dinosaurs. She also really enjoys feeling a sense of accomplishment. But sometimes I feel like she gets into a state of boredom/loneliness. She'll get mopey and I'll suggest things and she'll just say no and kind of just lay there doing nothing. I was wondering if there are any good pre-reader curriculum sets that aren't too intensive. She has a baby brother so it's a little harder for me to pay as much attention to her as she needs. So it would have to be casual. We're also very limited financially -- I catch as many trips to the nearby museums with friends as I can, but it's not an often thing. Eventually I'd like her to take the lead with her education -- I'm just trying to help her out for now.