As somebody who plans on cruising south from California in the future, I can tell you it's doable, but I don't think you have the budget.
If your budget is $25k for the boat, figure you could spend $10-15k on the boat, leaving you $10k to prep it for the trip.
A boat in that price range is not a blue water boat, so you're going to have to coastal cruise down, then cross over and hope the weather doesn't get you.
For your actual "cruising budget" you'd need to research the various stops you want to make along the way, to figure out what you'll be paying in fees, Ecuador is EXPENSIVE to cruise in, but figure you'll be paying every time you clear in and clear out of each country along the way. Consider additional costs for food, fuel, water, etc. Then you need an emergency fund, to fix things that break that you didn't plan for.
When I said it depends on the boat I meant it. Lets assume that you get a Vega 27 which is a very solid boat and more than adequate for the trip. On Yachtworld the asking prices seem to be $12 to $15k, so lets say you spent $12k on the purchase. There is no way you could spend another $13k on the upgrades unless a) you bought the wrong one and it is a piece of crap or b) you got all silly on upgrades (eg watermakers and the like). So, let's imagine $8 for upgrades which is generous, that means you have spent $20k. The other five can go for cruising expenses.
Ecuador is not that expensive to visit. The bureacracy is a pain and a bit pricey, but food, for example is great and incredibly cheap. Mexico and the other Central American countries are cheap from what people have told me, Panama is certainly cheap and a great place to provision (beer and good rum about $8 with being comparable). Other than the fees to be paid in the Galapagos it is not too bad assuming you are not doing much provisioning there (ie loaded up in cheaper places).
I don't see any problem in doing the trip following this sort of scenario. If you really insist on something in the the 34' range it becomes much more problematic and I don't see the budget stretching that far.