Rio Grande

Will I will let others answer the packraft questions but if you haven’t found it yet you might be interested in this trip report of a packraft and walk back across Big Bend from Big Bend Chat.

Using small watercraft is a pretty well known trip and all the pictures show it’s beautiful down in the Big Bend region … when there’s water.  It’s been known to get a little dry sometimes, moreso recently, so call the rangers.

The Rio Grande is controlled by various reservoirs to make its water useful to farmers in 3 states and 2 countries, so more and more the channel is dry to build up those allocations behind dam walls.  It’s recent nickname up by the Texas – New Mexico border at least is the “Rio Sand”.  Think that has resulted in more “portages” using traditional rafts down there.
Also the main water allocations come through in July – Aug and Sep so that’s usually when the channel is at its fullest (the authorities basically open the dam gates more).   Check the southern Colorado snow levels as the spring to summer melt is the main determinant for whether the systems will be full of water or not.  We actually did car portages up north of Las Cruces mid-summer (know your exit points if interested).

Not sure whether the Mexican side comes through with any additional water before or after Big Bend (Piedras Negras iirc).

The most popular pack (and my favorite) for packrafting is the HMG Porter 4400, at 70L, which is the same size as the Catalyst I think. I can fit my Yak w/ cruiser deck, paddle, CCF PFD, lightweight backpacking gear, and 3-5 days of food inside without having to resort to storing stuff on the outside. Big desert water carries might force you to lash stuff to the outside, but that pack should be good for almost any one-person boat if you fold it like this.