[MBZ] No Glow, No Start, Car Far from Home

[Bob Rentfro]

I came out to my car tonight after having worked my 6th 12 hour shift in a row at the old nuke plant...wanting nothing more than to get home, clean up and have a cocktail...and the old girl wouldn't start. I turned the key, got about a 0.5 second glow light then a faint buzz from beneath the dash somewhere (my seatbely alarm has never worked btw). Turn the key...nada. I checked the silver relays under the black cover on the wheelwell by the cruise control and they were seated well in their place, but the red wire going to the most forward one had come out of its connector. Those relays look identical. Is one the glow plug relay?
 
Remember...my car is 45 miles from my home. 
So...
If you were going to go and rescue it tomorrow, what would you take to be successful?  I'm thinking a new battery (I'm due...it had shown a little weakening lately) at least. What about those relays? I had no precursors of trouble at all. 

Any ideas? I get one whole day off to get 'er going again before I get to do a 5 days on, 1 day off, 4 nights on, one night off, 4 nights on stretch.

Thanks smart friends...

Bob Rentfro
'77 300D 152K
Litchfield Park, AZ