Honestly, for what I believe you are intending to make, that recipe seems a bit inappropriate for a coffee porter. And at 14% smoked malt (which would be fine for something like a Rauchbier) it would seem to me to be a bit overwhelming (put some Liquid Smoke in your coffee tomorrow if you don't believe me
). It's a very good base, though, and I would modify it in this way:
Baltic Coffee Porter
Size: 5 gallons
Est-Eff: 72%
PreBoil-Vol: 6.25 gal
PreBoil-Grav: 1.063
Boil Time: 60 minutes
SRM: 28
IBU: 33
OG: 1.077
FG: 1.020
ABV: 7.5%
Grains
5.5 lbs -- 2-Row Brewer's Malt (Briess)
1 lb -- Crystal 40L (Biess)
1 lb -- Munich 20L (Briess)
0.75 lb -- Barley, Flaked (Briess)
0.75 lb -- Barley, Roasted (Briess)
0.50 lb -- Carapils (Briess)
0.25 lb -- Chocolate Malt (Briess)
Mash Schedule (Full Body, Single Infusion)
Mash-In: 13.75 qts water (1.3 water:grain ratio) @ 172F (156F ST) for 60 minutes
Mash-Out: 5 qts water @ 207F (168F ST) for 10 minutes
Fly-Sparge: 3 gallons water @ 168F over 45 minutes
Other Fermentables
3 lbs -- Briess Golden Light DME @ 10 minutes left in boil
1 lb -- Clear Simplicity Candi Syrup @ Flame Out
Hop Schedule
0.50 oz -- Magnum (14% AA) @ 60 minutes
0.50 oz -- Hallertauer (4.8% AA) @ 30 minutes
0.50 oz -- Magnum (14% AA) @ 5 minutes
0.50 oz -- Hallertauer (4.8% AA) @ 5 minutes
Other Additions
1 tsp -- Irish Moss @ 30 minutes
Yeast
2 pkgs -- Wyeast Scottish Ale (1728) (2L simple starter or 1L Starter w/ stir plate)
Fermentation Schedule
Primary: 7 days @ 55-60F
Secondary: 21 days @ 55-60F
Bottle with 4oz Priming Sugar (Dextrose); 2.45 vol for 30 days
The few reasons I went with the Scottish Ale yeast for this is that lagers are finicky creatures. Any lager yeast you went with would require strict temperature controls, a massive starter (about 2 gallons without a stir plate), a diacetyl rest (we can talk more about that later) and a much longer time to ferment than I think your garage method of temp control would permit (well into mid to late spring). The Scottish Ale yeast permits cold temperature fermentations (as low as 55F) while still giving a clean, lager like profile without all the hassle and time of a lager yeast.
As far as the coffee flavor addition I would simply use the cold steep method and if you want to add some complexity to it, add about 2 tbsp of Cafe du Monde Chicory Coffee to some ground Starbucks Italian Roast. You don't need a French Press either if you don't have one; just mix the ground coffee with cold water in a sealed mason jar, shake, refrigerate overnight and run it through a paper filter or gold permanent filter before you bottle.