8 Days in Costa Rica-Skip Monteverde?
 

My fiance and I are currently planning our honeymoon in Costa Rica. We have 8-9 days. We are planning on staying in the Mt. Arenal area (Lost Iguana Resort) for 3 nights. From there, we want to make sure we have some beach time. In our original itinerary, we were planning on going to both Mt Arenal and Monteverde, but it seems like it would be too difficult to also squeeze in a couple nights at a beach given our time frame.

We are now planning on going to Mt. Arenal and Manuel Antonio. Would we be missing out if we skipped Monteverde? Also, if we do go to Manuel Antonio, are there any places worth stopping to break up the 6 hour drive or would you suggest heading straight from Mt. Arenal to Manuel Antonio in one shot?

The main things we want to do in Costa Rica are: hiking, ziplining, seeing wildlife, and going to the beach

Probably 5 hours or less. Be sure to stop at Tarcoles Bridge to look down on the huge crocodiles.
There's a lot to do in the Arenal area that is similar to Monteverde; zip lines, hanging bridge hikes (in the rainforest (vs. Monteverde cloud forest). Since your time is limited, I'd skip Monteverde (this time), and do lots of different beach visits in MA and southward (Uvita and Dominical).

I think you're fine to skip Monteverde. It's a long bumpy road to get there. Arenal has more to offer and better weather. MV can be really chilly. We had to wear sweatshirts at night there. We stopped at the Rio Tarcoles bridge to see the crocs, and it was very cool. Just don't leave anything in your car unattended. There's nice hiking in Arenal at the Hanging Bridges and the waterfall, Sky Trek is great for ziplining, and for wildlife we like the Cano Negro tour and the Penas Blancas river float - more wildlife at Cano Negro, but it's also an all day tour - worth it though. It didn't take us six hours to go from Arenal to Manuel Antonio - it was more like five for us. You can see a lot of wildlife (fairly tame) and visit the beach in Manuel Antonio. The beach inside the park is very pretty. If you eliminate Monteverde, you may want to spend the last night closer to the airport just for convenience. Grano de Oro is a nice city hotel, and Xandari is beautiful with great views if you can swing the cost. The Peace Lodge makes for a nice splurge for one night; it's about an hour from SJO.