Hi pjbphd:
I've run the stretch from LaLinda to Dryden about 15 times as a guide,
but the last time was about 10 years ago. However I might be able to
answer most of your questions.

An autumn trip might be a rough trip. The water drops through the
season, with most of the spring flows coming in from Mexico rather than
the US, which is not dam-controlled. As the mexican waterlevel drops,
the river becomes very rocky, teh flow rate decreases drastically, and
some of the more runnable rapids (Hot Springs, Upper Madison) become
total portages. My trips were all in March, and in the lower water
years, the river was downright bony. In high water years, the trip was
quite easy and by far the most fun. I am not certain, but my gut
feeling is that it might even be unrunnable in the fall.

It is absolutely! doable in hardshell open boats. I have only ever done
it in a canoe, and guided paddlers from near-novice level to experts. A
complete novice would be in trouble down there, as there is a severe
remoteness factor, but as long as the majority of the trip had
fair-to-middlin skills and could use good judgement, it would be a
great trip. Every risky rapid is portageable with easy to see portage
trails, but the difficulty of the rapids increase gradually at a pace
that helps develop skills at an excellent rate. The first few days are
all class 1-1+, the next few days have a few interspersed class 2's,
the next few days have a few easy class 3s, the next few days have a
few class 3+ or 4-s that can be portaged. The only *mandatory* portage
is Lower Madison, and its a brute. Search this newsgroup under
"riverman" and "lower Madison" for an old river tale about running that
stretch in an emergency.

The hikes and scenery are wonderful. I've never had any border problems
with anyone. The 'illegal immigrant' routes that cross the river are
near Hot Springs rapid, and you should time your trip to pass there
midday, so that you aren't camped near there. Other than that, you
won't see a soul unless its a sheep herder.

There is abundant cow**** everywhere on the mexican side, so US side
camps are cleaner. However, the geology seems to give the flat camps a
mexican-side preference. There are possible campsites everywhere, but
if you see a scenic ledge somewhere, grab it. It beats sleeping in a
field surrounded by cow ****. In the inner gorge, campsites are rarer,
but much more scenic. Watch for grassfires, as the riverside rushes
seem to catch fire spontaneously and you could lose your camp.

You can get up-to-date river guides at the ranger station at the park
entrance as you approach La Linda. My guidebooks are all in a box
somewhere, but there is a series of books on waterproof paper out there
somewhere that are very good.

Post any more questions you have here, and I'll be glad to reply.

--riverman