I created the following images to help explain the differences between solo and pool mining in Gridcoin. The charts provide a general overview of how your wallet and BOINC hosts fit into Gridcoin/BOINC ecosystem.
First up we have the diagram for a pool miner:
Next the diagram for a solo miner:
Last we have the diagram for an investor (for completeness):
If there is anything that is incorrect or unclear and you want it changed, let me know.
Also, feel free to make a modified version.