As you correctly said, the armed forces of Venezuela are no match for the U.S. military and would see it as pointless to try to take them on directly.
The logical strategy would be let the U.S. and our lackeys invade then fight an asymmetric war. A lone water-buffalo and a guy with a rifle looks exactly what I would expect, and I expect that Venezuela has been preparing for asymmetric warfare for 20 years now. We all knew that this day was coming.
---
The U.S., in conjunction with the international bankers who own the USD federal reserve notes which constitute the world reserve currency, have killed people by the hundreds of thousand through sanctions in the past and have in effect bragged about it. See M. Albright and Iraq. Just recently they were bragging about Iran needing to play our game or their people do not eat.
As much as a lot of us detest socialism we're not going to ignore the dedicate efforts that the U.S. has made in trying to destabilize Venezuela through economic means and the impacts that that has had on the country.
In other words, the propaganda that Venezuela's problems are wholly a result of their own socialist economic system is a dog which won't hunt for anyone with at least a little bit of a clue.
You are assuming everyone will go out to "defend" against a "foreign invader", but that is not the case. Maduro does not have the ability to rally enough supporters as you may think... 30million? Already 4million fled the country, take out the children and the elderly, you are left with like 15million able. But from those... 80% oppose Maduro, you are down to 3million. Of those at least 2million are militia, as in, civilians with barely any training, beyond parading and some occasional physical exercises (i will spare you the meme jokes from videos of their activities). The military in Venezuela are no more than 100k, assuming no one would surrender or turn traitor. But don't forget the 80% discontent does include the military, and even among the Maduro supporters, not everyone able is going to pick up a rifle (and might not have access to, anyway) and do violence to risk getting killed...
If you look at Libya, NATO didn't bother with troops on the ground, they mostly just did air support to rebels and mercenaries, and that was conventional human piloted air support. The doctrine of asymmetric warfare was developed for a previous pre-unmanned era, they expect boots on the ground to shoot at... What happens if a sniper shoots where the air space is controlled 24/7 by unmanned aerial vehicles? He is instantly spotted and dealt with. The doctrine is useless against the unmanned aircraft, so what if you can take down a few, more will come. But each of your casualties is unrecoverable. They can't go guerrilla hiding like in the past, even the half century old guerrillas of Colombia have been defeated and or pacified (because they saw no choice) one by one.
In fact sooner than later even ground operations will be performed by remote controlled automated units, tho i don't think that is available quite yet.
I can talk to you about the "dedicated efforts" the US tried to destabilize Venezuela, under Chavez they got close but failed, but you already know that...
No, under Maduro it wasn't the US, it was Maduro himself. Maduro inherited tremendous international support and money, all done by Chavez, he burned it all, not just the money, but the trust. Even Russia is now showing signs of distancing away, but that was expected given the little involvement with Venezuela, beyond the occasional parade of the same two old bomber planes or the rare visit of their military ships. Now that i remember China once sent a hospital ship as well, not sure if its still here, it was technically a military vessel performing a humanitarian mission (red cross etc).
Now other countries are sending humanitarian aid as well, but Maduro's response is this:
What do you think should/will happen next?
Do not be mistaken, the vast majority of the people from Venezuela want Maduro and his lackeys gone. You can argue he didn't do "true" socialism if you want (Guidó's party is technically socialist, it belongs to the international socialist) but that doesn't change the sentiment against Maduro, he built that upon himself thru his own actions and some of his close people. Mind you, there is a significant former Chavez supporters, including ex-ministers and party members, who are against Maduro and are even supporting Guaidó. Rafael Ramirez has publicly stated he wants to run for elections to "restore" the project Chavez left.
I do not support them nor socialism, especially any system that involves "controlling" the economy, that doesn't work, and never will. Despite the problems, the poor live much better in a free market economy than in a socialist (controlled) economy. "Free things" involve a cost too high to pay in the end: The misery of everyone but those select elite few that manage to stay close to the ruler or his close circle...