Adrian, I use the dr-2d, and often run 4 channels with either CA14s or bsc1s into the mic in, in either case using a Naint preamp between the mics and the recorder.
I use the line in with the SBD feed.
The dr-2d hasn't ever caused me an issue overloading with too hot a signal, and I have never asked the engineer to turn down the signal. I also have never used attenuators to lower the signal. Maybe I have just been lucky?
For cables, I have a couple of long L/R RCA > 3.5 miniplug cables that I connect to the SBD with. Most times I can plug the RCAs directly into the SBD, then go direct to the dr-2d line in. For other connection types from the SBD I have a bunch of adapters (RCA female > XLR male, RCA female > XLR female, RCA female > XLR male, a couple of RCA female > female adapters). I think that is everything I have and it has covered any situation I have encountered with board access.
Again no issue with too hot a signal for me, but maybe others have had problems. You could always use an inline attenuator/pad instead of an actual cable in case you needed it.
Colin