Woah!! the Holy Grail, that's all
You will be able, if you're lucky, to sample the three beers they produce at the bar In De Vrede, attached to the monastery. The 6% is a very pleasing, hoppy, refreshing beer; the 8% is a powerful, dark, brew, like anybody else's 12%... and I don't yet know what the 12% is like, but many connoisseurs consider it the finest beer in the world. Probably not ideal for cycling on
I hope your itinerary also includes the nearby village of Watou. Less than 2000 people, and three breweries! Poperings Hommelbier, available on draught there, is not too strong and a very fine beer indeed. You will be too late for the savoury tart made with hop shoots, though...
The scenery round Westvleteren is nothing to write home about, but if you go a bit further south and east you are in lovely Heuvelland, straddling the French border, a delightful area of gentle, wooded hills - heavily fought over in WW1, but only the (wonderfully well-kept) cemeteries give a clue to its violent past now.