Well, my trip to the southeast corner of California and the vicinity
is complete and was more or less successful. I won't know for sure
until I develop the photos, at which point I'll scan them in for you
guys. Here's what I learned:

1. It is far better to cross into the United States from Mexico in a
little town than a big town or a city. I crossed from the USA into
Mexico in Tecate and Algodones, and in both places there was no
waiting or almost no waiting in the opposite direction.
Unfortunately I decided to cross back into the USA from Mexicali
(main crossing) and San Luis Rio Colorado, and it both places the
traffic jam lasted about an hour.

2. In Algodones, you can find the northeast corner of the paved
network of streets in the town; it is just east of the little
canal/stream that passes through the middle of town and right up
against the border, which is easily recognizable as a 10 foot high
metal fence. You can park in a little dirt lot there if you pay a
dollar. Then you can walk over to the river to your east. There's an
undeveloped strip of land between the parking lot and the tripoint
about 50 meters wide or so. It's sand and dirt wish some bushes and
some junk. There's a monument (#206) a little ways in marking the
Mexican side of the border. Once you start getting close, the bushes
start to get pretty thick, but there are person-sized pathways
cleared through these things, if you hunch over. About 20 feet from
the Colorado River, the border fence actually ends! So you could
actually just walk across to the USA if you wanted, but on the USA
side there's a dirt road cleared for Border Patrol trucks; I imagine
they keep an eye on things. I stayed on the Mexico side and made my
way toward the river. About the last 10 feet before the embankment
drops off are completely overgrown with 8 foot high reeds. You can
push these reeds out of the way, but you'll get sticky reed stuff
(sap?) all over you. That's what I did. I got to the edge of the
embankment and had a view of the river, but I couldn't clear all of
the reeds out of my way or else I would have fallen in. Looking
around, I didn't see anything obviously pointing out where the
border was, even I was within about 2 meters of it. So I took two
pictures of the river from where I stood, with it partially obscured
by a few of the sticky reeds. The tripoint will be located somewhere
in the middle of the river in the photos. Not rock solid, but I know
that the tripoint was somewhere in the vicinity of what I was
looking at.

2. The azbcson tripoint kinda snuck up on me. All of a sudden there
was a bridge, and then there was a sign telling me I was crossing
the municipio boundary, and I looked to my left and saw the usmx
border fence disappearing into the river. So the tripoint was in
there. But traffic was moving and up ahead was another tollbooth. So
I didn't feel like pulling over, and I didn't take a picture.
Crossing the usmx border a little while later, they asked what I was
doing and I actually told them. The fact that I had crossed the
border in Calexico the day before had set off some kind of a red
flag in their computer, but when I told them what I was up to, I
guess it sounded too bizarre to be a false story, so they made a
quick search of the back seat and the trunk and set me on my way.
The closest thing I had to contraband was a couple of empty
returnable Mexican Coca-Cola bottles (they make it with sugar in
Mexico instead of corn syrup, so it tastes better), so they didn't
have any legitimate reason to harass me anyway. My friend had his
passport, and I had my driver's license and my borth certificate.

3. Later we drove up into Imperial County CA and found the exact 33N
115W degree confluence with our GPS receivers, a few miles east of
the Imperial Sand Dunes. Parking was easy off of CA-78, and the hike
was about a mile due south over easy, flat, gravelly desert. I took
photos at the confluence point and will be submitting them to
confluence.org. This one was a lot easier to actually get to than
the tripoints. You'd need a boat and some sort of immunity from
border patrol guards to actually float over the azbcca and azbcson
tripoints.

Adam