The only hard advice I can offer is--DO NOT rent a car in CR. Unless you are experienced in driving in, say, Afghanistan, it can ruin your vacation quickly. The airlines mentioned are a reasonable option but Costs Rica has excellent private bus service everywhere and not on some "chicken bus" either. It'll take longer that way natch but you'll see some great scenery up close and personal. The Brothers were correct about P4P; for a novice it doesn't exist outside San Jose and Jaco. This is your first time in CR (recon mission) so go with the flow; later on in life (like, for example a month after you get back to what we charmingly call Gringaland), come on down and get the best of the rest. Frankly, I'd take advantage of the ups and extras the resort has to offer with maybe 2 days in SJ.
BTW, congrats on having such a great job that sends you here AND lets you take personal time incountry--we should all be so lucky/ skilled.
www.flysansa.com
www.natureair.com Their planes meet/ exceed FAA standards
www.costa-rica-guide.com/travel/index.p ... Itemid=684
Soft Pitch: If you decide to come to SJ for some days, seriously consider joining us as a paid member--The nominal cost ($39/yr; $99/Lifetime) will easily recouped in the discounts on hotels, restaurants, fishing trips, even dental services plus access to members-only Forums--it's not a cost, it's an investment.