It's rare not to find at least one tree or pole. In such cases one can use the seat post of a bike as the other end to support a hammock. Here's an example I posted on Hammockforums:

https://www.hammockforums.net/forum/...-Hammock-Stand

I also experimented with portal, one-tree hammock stands that could be combined with a bike to support a hammock:

https://www.hammockforums.net/forum/...-hammock-stand

It would be possible to develop a relatively lightweight version of this. The total weight of the example I provide above is 27oz.