YMMV, (you mileage may vary). Usually 1 day per 10 miles of
racing. But your horse may need more or less. Probably should at
least walk them around some so as to help with sore muscles. Just like
humans, stretch those muscles. Just remember a race does not build up a
horse or rider, it breaks you down. Rest brings you back, better and
stronger. Just like working out in a gym. You lift weights, it tears
you muscles down, rest and they heal stronger and bigger.
"maybe 2 or 3 weeks, prior to a 100 mile ride,
and then 2-4 weeks off after as well. Can anyone with years of experience with
100's, tell me if this usually complete time off, with
only pasture turn-out, or, are the horses usually still ridden
lightly."
2-4 after the 100 is easy--absolutely a good
idea, so long as there is adequate turnout. I wait until my horse "asks"
to go out on trail again.