Little baby's are tough to travel with so we keep our expectations low and our activities relaxing. You have to consider how tough diaper changes and feedings can be in a crowded public place or your average hotel room. It's more work than it's worth.
We love to rent cabins and houses on the beach or in state park forests. We have access to all the comforts of home and it's private and quiet. We move at our own pace and go for walks and picnics. At 9 months old even a blade of grass or flower is very facinating. For us, enjoying nature and being away from the daily grind is a huge recharge.
I personally think being away from home is stimulating enough without all the amusment park crazyness on top of it. When we've taken him to the zoo or amusment park we always have to leave early because he's tired and out-of-sorts. With our last zoo visit at 8 months old he woke up screaming from night terrors that night.
Now that he's 18 months old he really enjoys the high levels of stimulation and handles it much better.