Just the front, or are you thinking of driving the whole thing up on ramps?
I've used those old style metal ramps with cars, and they're fine unless you drive off the end! I procured a second set, and would either carefully drive the front on to them and jack up the rear and use them as stands under the rear tires, or put them back to back in the front so there was not danger of driving off the end, there would be a "bump" and the tires would go on top of the front set. I started using a pole in front of the car to bump when the tires were on top (used a tape measure to place pole).
Another good way to get it off the ground to work underneath is to get a good floor jack (or two) with the twist handle to lock the pump, and place jack stands under the van, or blocking under the tires. I got rid of my ramps and just use a floor jack now, or two; I have two. Tip: you need a long throw jack for the Transit, or some sort of blocking on top of the jack head like a stack of short 2x6 or a chunk of 4x4 or 4x6.
I have a set of Rhinoramps plastic ramps. Their weight rating (12,000 GVWR) is more than enough for a loaded van.
I have noticed over years of use that occasionally they will slide as you attempt to go up them. They have rubber strips on the bottom that are supposed to prevent that. But they don't always work, especially when using on a smooth garage floor.