…it will still get dark during totality — much darker than if it's clear, in fact — but that won't be your goal. Because a few seconds of clear totality are better than a long duration of cloudy totality, weather is more important than the duration of totality.
Indeed. So clouds will be the big question for the April eclipse. It will be another hit or miss circumstance. The arid regions of Mexico might be a slightly better alternative to most of the US umbral path, but it only gains a few seconds of totality over the drier regions of Texas.
Annual rainfall in San Antonio is only ~29”, but only ~15” on the border with Mexico.
But going west from San Antonio along IH10 moves you into more arid regions. Kerrville will be very close to the center of the path, and it is a little drier than most Texas cities along the path, ignoring the border region.
But, if you wish to maximize your enjoyment, and mitigate for clouds, I suggest you travelers to consider a combo treat -- Junction and the McDonald Obs. This is the last city before making the 1500 mile westward trek to the next non-desert like region (west coast of CA). You will still have a little over 3 minutes of totality viewing, but more than the time from the last total eclipse crossing the US. Junction also has only about 13" of annual rainfall.
But, after seeing the eclipse from Junction on Monday, you can then travel to see the McDonald observatory the next day. [They are normally closed on Sunday, but open Tuesday.] They have many treats for visitors including a great visitors center.
[It's possible they will host something special but, in spite of my encouragement to do so, they might not unless many request something. No doubt they too will be set on seeing the eclipse, but Tuesday is, as they say, another day.]