Hi Pete Z,
That itinerary is totally doable with 17 days- 17 days is a long time! Basically, what you have is what we recommend for a 2 week itinerary plus you’re adding on Puerto Viejo. So we’d recommend starting by looking at our Two Week Itinerary blog post to figure out the best order to minimize travel time. That post is more of a general overview of each destination, but it links to other more detailed posts we’ve written on the Arenal area, Manuel Antonio, and Drake Bay that you should check out. The more detailed posts are loaded with info on getting around, hotels, restaurants, etc.
Then for Puerto Viejo, we’d recommend adding that to the beginning of the itinerary before you go to Arenal/La Fortuna. The Caribbean side is a little far from San Jose airport, but the roads to Puerto Viejo are all good, well maintained highways so the drive really isn’t all that bad. Then after, you can drive La Fortuna in one day or break it up with an overnight somewhere on the way. Puerto Viejo has a totally different feel from the rest of the country so it is worth going. Of course it’ll mean having less time in the other places you’re going, so if you are looking to delete one destination, Puerto Viejo would make the most sense.