I haven't played Fallout 3 in a long time but I did go on the Fallout wiki and it only listed 1 type A encounter near Vault 101.
On the top of the hill westwards near the highway, there is a farmhouse with the event. Any approach will work.
This one is a type B:
Follow the road south until passing between the highway remains and the pillar, where the road turns W. Then go back on the road, the event is halfway between Vault 101 and the water tower.
Both of these are listed as Vault 101 encounters. The wiki doesn't say what should get out of these but saving prior to the encounter is recommended because there are multiple outcomes and you can reload if don't get the one you want. Sorry I can't be much more help