Sounds like you might have a Muscadine (Vitis rotundifolia) it is a native wild grape of the southeast we have some here by our woods growing on some tree branches and I like them a lot they have unique taste.

Pruning: Annual pruning must be severe to keep new fruiting wood coming and to prevent vines from becoming tangled masses of unproductive wood. The basic framework of a vine consists of the trunk, permanent arms, and the fruiting spurs. Vines must be pruned each dormant season to maintain this framework. Current season shoots bear the fruit, but to be productive, these shoots must arise from buds set on last season's growth, since shoots from older wood are generally sterile. It is important to leave the correct amount of fruiting wood.

Pruning is basically the same for all trellis systems. Only the arrangement of the fruiting arm is different. Two systems of training are used, the upright or vertical and the overhead or horizontal system. In the upright system, a 3-wire trellis is used, the lower wire being 2 ft. from the ground and the others 2 ft. apart. On the trellis the arms may be horizontal along the wires or fan-shaped from a low trunk. With this system the cane is taken to the top wire and the first year or when vigorous enough, and then topped to make it branch. The resulting laterals are trained along the wire to make the arms.

The overhead trellis provides more bearing surface per vine. The vines form a complete canopy about 7 ft. from the ground. The vines are trained to a single trunk 7 ft. tall with the arms radiating from the top of the trunk like spokes of a wheel. A mature vine will have about 8 arms. During the dormant season each year, cut back all shoot growth of the past summer to fruiting spurs 4 to 5 in. long. Remove shoots entirely that are not needed for spurs of fruiting arms. On young vines leave spurs of one year fruiting wood about 6 in. apart. As the vines get older, they develop clusters of spurs, or spur systems. Generally, thinning of these spurs is necessary after the fourth or fifth fruiting year. This thinning will force new spur growth to replace older spurs.
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Muscadine
Muscadine
Muscadine
Muscadine

Yup that's what they are.

Non of the information I found or read addressed what to do with one found growing in the wild, regarding pruning it to a manageable form and for fruit production.

So should I just chop it off a few feet from the base and hope it sprouts some new shoots, or is it worthless as it's over 30' long with the only buds at the end?

Or could I string it up and just start the current new growth growing back towards the main trunk?

I'm not sure if they will sprout from the base of old wood, I have a feeling that they probably would but I'm not totally sure. Maybe someone else knows on here.

Anyone else think they will sprout if i chop them off?

I choped them off, I guess we will see if the sprout.

Well it's been 9 days, one vine is still bleeding! There also appears to be the beginning of buds, we'll see!

O.K., I think this is what I want.....right?

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Update:
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So I guess it worked.