Rereading some of the older posts on Lunar exploration, I ran into a lot of discussion on short term vs permanent outposts or bases. The assumption seems to be that short sortie missions will have minimal or even no radiation protection.
A quick thought is that a foxhole approach might be worth looking into for the short sortie or light mobile base concepts. Troops in the field that are likely to get shot at often dig or blast a small hole for shelter. Nothing is assumed to come from below, horizontal incoming is eliminated, and danger is reduced to vertical from above. Then the danger from above is often reduced with logs, sandbags, or even bodies in extreme cases.
With the foxhole model, it seems possible that a small hole can be created in the lower section of a crater to provide radiation protection from 80% of the sky not already covered by the planet. The hab section is lowered into the hole. Then the lander or wheeled vehicle can be parked over the top of the hole to help shield the remaining exposed directions from cosmic radiation. Solar radiation can be almost entirely eliminated from hitting the hab module.
With no high value real estate to destroy, or neighbors to annoy, the hole could be impact from a trans lunar projectile at 2,300 m/s. It could also be explosive, mechanically dug, or pneumatic Â as Jon has posted about.