Sorry, no help here; not that sort of puzzle :P
Please note some of the locations you'll visit aren't open 24/7 but none charge for entry. Please read the cache page carefully. The hunt may take you over an hour. The puzzle element; considerably longer!
Locations in a logical visit order:
N51° 45.045 W001° 14.964 (Same as cache page)
N51° 45.152 W001° 15.145
N51° 45.239 W001° 15.263
N51° 45.285 W001° 15.192
N51° 45.514 W001° 15.363
N51° 45.229 W001° 15.528
N51° 45.130 W001° 15.484
Questions in no particular order:
Witch, Bat, Fish Hat! You're standing outside a large building that's open from 10am 'til 5pm daily. However! You'll want to be here from noon to 4.30pm on Mondays and 10am to 4.30pm Tuesday to Sunday (and bank holiday Mondays). Enter and proceed past a Lewis Carroll inspiring bird to a doorway on the back wall. If you've not been here before, prepare yourself to step into a world worthy of Harry Potter. It'll be a bit dark, so allow time for your eyes to adjust. You're looking for the last word about C31A-1926.6.1 (not a person's name), the word after 'Called' describing L10A-1910.42.15 and the first word after 16. about U4A-1884.32.31.
Full Of... ...near this place~ J October KLMJ. First English what? Fun fact: You're within sight of the world's oldest botanical garden here. It's a short distance to the north-east.
Naughty Boy! You're outside an Inn which had already been in existance for almost three centuries when it acquired its present name in 1GHI. Whom is said to have been 'more than friendly to John's wife'? (Surname only)
The Oldest Building. You're standing outside what's alleged to be Oxford's oldest standing structure. It's Saxon in era, built before the Norman Conquest in 1066. Which saint is it named after? (Drop the St.)
Hidden Treasure. One of Oxford's. Morse and Lewis knew about it though. So did a Pre-Raphaelite Muse, who was born here-abouts in October of 1ABC. You also need to collect her maiden surname.
Super Cell? A location famed for several things. A plaque tells you about a couple. The black box on the otherside of the road isn't the UK's oldest weather station, as I'd been told, but that isn't far away: The Radcliffe Meteorological Station is situated in the garden of Green Templeton College on Woodstock Road. Back to the here and - then, not now - and a couple of Bobbies. One 'made experiments' with a what designed by the other? Treat the answer as two words for the puzzle. Dates: 16NN - 16OP.
How's your Latin? Thomas Montgom is waiting for you here. He may not always be reached and if he replies to your spoken questions you're talking to the wrong man. He'll be wearing a very fine suit and sporting a handsome beard and stands above a date in the Roman style: 1DEF. You also need to gather the only recognisably English word below his moniker.
Puzzle:
Final location:
N51° 4(A-F).(O-G)(A+B+C+D+E+F+G+H+I+J+J+K+L+M+N+O+P)
W001° 15.(E+H)(B+K)(P-N).
Here you'll need to enter the imposing building to the east of you and give the password phrase.
Think you can cheat the system and grab the cache? Don't forget the password phrase you'll need!
Read more about The Historic Geocaches' campaign.