You could put 3 plants, 2 at one end of your bed at each side, the other one at the other end but in the middle, as they grow direct the vines the way you want them to go and train them to grow to the other end,they will grow this long. This is only 3 plants which doesn't sound much but it is not a big area pumpkin wise,You may get away with 2 at each end. You can let the plant drop off the bed and let them wind along the paths too. I personally would only put one at each end but this is hard unless you have a lot of space. Spacing for good pumpkins is actually 12 foot apart in all directions, personally I have to go closer than that, but they will compete for light and food if too close and you will lose on yield too. your two pumkins mentioned are both big.
Hope this helps.