The one on the dead vine may or may not turn all orange, and it may shrivel and/or mold quite soon. If you can think of a use for it by all means go for it. Maybe it would look nice on the front porch, maybe it's for the compost bin.
Regarding the large pumpkin, it depends what you want to use it for. In general, you want to leave it on the vine until the vines shrivel and die. That's how you would typically ripen a pumpkin. That would maximize its shelf-life and its length of use for a seasonal decoration. If you're going to make a Jack-O-Lantern out of it and the vines aren't dying I would just harvest it as late as possible and use it as is. If the vines die long before Halloween, then harvest it leaving as much stem as possible and hold it in a cool, dry, frost-free location until carving time.

Thanks for your reply. I have already cut both pumpkins. The stem of the little one was turning yellow so I decided to cut it. The larger one had turned completely orange so I decided to cut it too, although from your post I guess I should have left it on the vine. I left both in the sun for a few days then moved them into the dark garage. I wanted to use that bed for fall planting since the summer crop seemed to be done.

They are supposed to be pie pumpkins so I may have to cook it/them soon rather than storing them till later.

When you grow pumpkins or other winter squashes, you should assume that area of your garden will be occupied until the end of the growing season.
One way some people use to judge pumpkin ripeness is to press a thumbnail into the pumpkin's skin. If the thumbnail penetrates easily, it is not ripe. If it resists your thumbnail then it is likely to be ripe. The color is not a good indicator since, depending on variety, a pumpkin can turn orange long before it is ripe and may still need significant time to sweeten and develop its full flavor.

I wish that I had known all of this a few weeks ago. I just checked the 2 pumpkins, the small one I can pierce the skin with my fingernail which isn't a surprise, I didn't think it was mature. The other one has a hard skin--yay! Hopefully it will have a good flavor and texture. I had originally intended to let the vining crops stay in that area until they were done, probably sometime in October, but when it seemed like the pumpkins were done so early I figured I could get a crop of winter zucchini out of that space. In my part of San Diego we don't really have defined growing seasons, in summer it gets too hot for cool season crops (except for this past summer which was unusually cool) but some warm weather crops will grow year round. Now I know for next year if I decide to do pumpkins again--I didn't get much return for my efforts or garden space with them. The spaghetti squash in the same area are still doing well.

Thank you so much for your advice.