I was reading your blog (I assume you don't mind "losing" your
anonymity) and you wondered about speed training. Any good book about
track, X-country, road racing or marathoning can help you, but the
basics as I learned them are as follows:

You train in cycles to peak for certain events or seasons. You start
with only distance runs to build endurance and strength (your base).
Then gradually you replace the distance runs with speed workouts in
shorter intervals, closer to the race pace you want to achieve. You mix
in technique work (for O, map reading, I guess although in the track and
field world they are talking about physical technique, not mental. Maybe
for O it would be more running in the woods as opposed to the roads.)
Then as the big event approaches, you back off on the intensity to stay
fresh for races.

A typical "off-season" routine might be distance runs 4 days a week with
one day of rest and 2 days of Cross-training; some other sport to keep
the body fresh. Some weight lifting might be a good idea too, especialy
if you have some weakness due to injury.

Pre-season might be 3 days distance and 3 days long intervals, 400 -
800m with full recoveries

In-season you might race Sunday, long run Monday, a mixture of middle
and short intervals with shorter recoveries on Tuesday - Friday and rest
Sat. At our age, you might throw in an additional rest day during the
week. Listen to your body and don't overtrain. If you feel you need more
endurace, make the intevals longer; need more speed, do shorter, faster
intervals.

Keep the interval workouts short and to the point. Run at race pace or
faster. For example, run 2-3 500-800M legs through the woods at slightly
faster than your desired race pace with only a minute recovery. DOn't
forget a good warm-up and warm-down. I think interval training is doubly
important for O because the entire race is one big interval workout.

A season is usually one year, but 1/2 year cycles could work too.
Olympic Athletes even have 4 year meta-cycles on top of the yearly
cycles.

I haven't read any O-specific training literature, this is based on my
Track and X-country experience. I'm sure O-training routines work
technique into the mix also.