I had originally intended to discuss designing encounters and obstacles in solos in Part 2, but the release of Tom Grimshaw's mini-solo "The Blood War of Saxon" in the first issue of TrollsZine has inspired me to discuss the addition of random events. "Blood War" is a short (44 paragraphs) solo that takes place in a small tomb. But with a set of nicely developed random elements, Tom has made it so that this solo can be played several times with different results.
The addition of random elements can greatly enhance a solitaire adventure. Normally this is done by adding random or wandering monsters that may show up while the lone delver is exploring. But there is no reason why regular elements of the tomb, haunted castle, or dark forest cannot be random as well. Who says the dining room always has to be empty or there are always two skeletons in the crypt? In "Blood War" some doors open to rooms whose content is determined by a roll of 1d6. Grabbing for treasure also has different results depending on what you roll. It certainly keeps you on your toes.
This feature also adds to the replay value of an adventure. With these random elements you can't assume you know the best course of action the second or even third time through an adventure. So you think that chest is full of one thousand gold coins ripe for the taking? Well, guess again. That was when Omar the Dwarf was here. He was killed by the zombie two rooms over. Now the chest contains one thousand flesh-eating ants. You're dead now too by the way.
But of course you don't want to overdo the randomness. The trick is to add just a touch of chaos to the mix but keep your unifying themes intact.