Costa Rica is a beautiful & fun place to take a vacation, esp. with kids & friends!
Went years ago with hubby & his family. We planned it out to experience 3 very different areas of Costa Rica - San Jose (capital city), the west coast, & the cloud forest.
I don't remember what hotel we stayed @ in San Jose, but we were there only the night we arrived, & then between the coast & the forest. Just enough to get a feel for the hustle & bustle of the culture. I do remember the hotel was within 1mile walking distance to a big shopping mall, filled with lots of touristy shops, but also authentic arts & wares.
On the west Coast, we stayed @ the Drake Bay Wilderness resort on the Osa Penninsula http://www.drakebay.com/
This place is fantastic. Very small, all-inclusive, packages include different guided tours & other activities. A few standout activities we did were a horseback ride to a butterfly farm, & then back down the beach, and a trip to an island with a waterfall where they served lunch.
Food was outstanding - we did a deep sea fishing one day, & they prepared the fish I caught for dinner, & my husbands fish was laid out for breakfast the next day!
In the Monteverde cloud forest, I don't remember the specific hotel we stayed at. They are hotels, not resorts, so activities can be on your own. This link helps with information about lodging & activites, etc. http://www.monteverdeinfo.com/index.html
I do remember we took a horseback ride to a waterfall (there was also some hiking involved). My SIL went zip-lining through the canopy & loved it. A number of guided tours are available, & I remember one that included suspension bridges, quite the views!
Now, with all that being said, it can be very daunting to plan a trip that takes care of all the lodging, transportation & activities, esp. for so many people, & if you want to visit different areas. Truly, you could do a vacation just on the coast, or just in the cloud forest, spend a week & still feel like there is lots to see!
My suggestion is to take a look @ websites & get a feel for the different regions, what activities they offer, etc. and then contact a travel agent to see if there are packages available.
One last thing - many places offer seasonal discounts. In Costa Rica, the rainy or "wet" season is considered the off-season. This is when we took our vacation, & all I can say is that it just means that there is a small rain shower @ 2pm every day, and the humidity in the air prevents your clothes from completely drying if you lay them out at night. But the humidity is not the oppressive, take-your-breath-away smuck that we have in the midwest, it really wasn't a problem at all.
I'm so jealous!! Go & have a fabulous time! T.