Once they are solid orange they are ready to pick. You can leave them on longer if you want but don't need to, once you remove the pumpkins the vines would probably try to make more pumpkins (and yes there is enough time). If you cut all the leaves off you might as well pick the pumpkin cause it won't be getting anything really from the vine.

Thanks. Taking out the vines will help free up some walking space in the garden.