In my Tor Browser Bundle's (TBB's) 'torrc' file I have set 'EntryNode' to my node's fingerprint. This means that the TBB uses my node as its "guard/entry" relay. By monitoring my node with 'arm' I can see that this is working just as I expected.
This is only a temporary arrangement to help me explore the TBB and my (separately hosted) Tor node further. But I am curious as to whether this could be a longer-term arrangement. If I trust my laptop with the TBB on it then I also trust the box next to it that is running my Tor node!
What are the risks/downside of operating the TBB in this way? For this test I am only browsing harmless sites that provide a conistent download stream which I can monitor with 'arm'.
NOTES: On my Windows 8 system the TBB 'torrc' file (which is empty initially) is in the ~\Desktop\Tor Browser\Data\Tor folder. When I restarted the TBB after editing 'torrc', TBB immediately picked up my Tor node as its "guard/entry" relay.