1) yes, they can all be done as day tours
2) no, the volcanos aren't far
3) yes, it tends to rain mainly in the afternoon
4) anywhere from $35 for a half day tour to $90 for a full day tour, plus any tips
5) sure, you can also do it very easily through the tour-desk in the lobby of the Del Rey.
6) this can be done as a day tour from SJ but you will have to add the $20(?) cost of a license, the cost AND TIME of getting to the coast and the timeof getting out to the fishing spot. It might be something done better as part of an overnight to Jaco which still has nightlife. Expect to pay $230-240 for a NON-charter out of SJ which includes everything except for tips. Charters generally run anywhere from $600/half day for a
small boat to much more so it will probably cost at least as much when you get done with transfers, licenses, etc. You'll be there during the green season so you might find better bargains, but it will still probably cost twice as much as the other tours you mentioned. Does that sound reasonable?
You really should use the search feature. Here are some of the MANY links to highly detailed threads on the subject of day tours:
CRT Fishing VIP Discount Programs:
http://www.costaricaticas.com/phpBB2/viewtopic.php?t=1529
http://www.costaricaticas.com/news.php?id=137
http://www.centralamerica.com/cr/tours/jdfish.htm no special discount(?) but a major operator.
http://www.costaricaticas.com/phpBB2/viewtopic.php?t=5770 Various CRT perspectives on fishing
New ATV Tour with CRT VIP Discount:
http://www.costaricaticas.com/phpBB2/viewtopic.php?t=8470
Canopy Tour Review:
http://www.costaricaticas.com/phpBB2/viewtopic.php?t=4850
Rafting:
http://www.costaricaticas.com/phpBB2/viewtopic.php?t=8005 more info in general section below
Volcano Tours:
http://www.costaricaticas.com/phpBB2/viewtopic.php?t=4959
http://www.costaricaticas.com/phpBB2/viewtopic.php?t=139
Multi-Activity Tours:
http://www.costaricaticas.com/phpBB2/viewtopic.php?t=7882 1 day horseback-canopy-raft tour, see general section for info on the 4-in-1 tour.
Couldn't find a thread specifically on biking but its covered in the general section below.
Day Tours in general:
http://www.costaricaticas.com/phpBB2/viewtopic.php?t=6059
http://www.costaricaticas.com/phpBB2/viewtopic.php?t=7745