Here's something I'm working on that's related to condensing an entire campaign down to two pages: for the campaign I ran recently, I drew up some standard square and round tower layouts. Ground floor, middle floor(s) and rooftop, plus two or three layouts for ruined layers. The idea is that most towers are pretty much the same, so I could make notes for individual towers without drawing up individual maps. This isn't original; somewhere, I have a copy of Frontier Forts of Kelnore, which as I recall worked in a similar way, with the GM rolling for variations when placing a new fort (I'm hazy on the details because I inherited the module, but didn't run it; my friend used it when it was his turn to GM.)
This approach can work well for a number of campaign element, which can save a lot of space. For example, for hamlets and small villages, you can roll 2d6 for the number of buildings and just assume that the village is the intersection of two or three roads, eliminating any real need for a map. Castles are a good candidate for random variants of standard patterns, too... so I've been putting together a generic castle "map".
I haven't completed any tables for this yet, but you will note that each of the six sections has a different tower shape and a number, so that you could roll a d6 to determine the shape used for all towers. You can also use these numbers to determine which sections are missing, either because the castle was constructed that way (curtain wall runs diagonally from B to the gatehouse, for example) or the walls were breached. Similarly, you can use a d6 roll to determine which (ruined) tower is the tallest and which is the lowest, then roll a d4 for either extreme, treating a 4 as "no above-ground structure."