Is this forest part of your
land? If so is it in the realm of possibilities that you might be thinning trees in the future? What is the orientation of your garden in relation to the sun's travel?
Most of the plants you mention like to have more than 5 hours of full sun to produce well, which means you are
gardening in a spot that might not be close to ideal and that will eventually create more problems.
As for your question, we use
cattle panels (4 feet tall and 16 feet long) to trellis our beans and we also have one for a tomato trellis.
The panels we use for beans are attached to the ground on the ends and they arch over a 2 foot wide
garden bed that gets shade loving herbs planted in it under the arch .
The tomatoes are planted in
straw bales (we get ours from an organic farmer) with the panel running the 16 feet of bales, the tomatoes are tied to this so we can harvest easier.
The arched panels are held in place with sections of rebar driven into the ground, they are attached with 3 wraps of bailing wire in two places so they are firmly in place.
The tomato panel is held by three, evenly spaced T posts and again bailing wire holds the panel to the posts.
Another method that might work for you is the 3 or 4 pole tipi style support.