I use to use 2 5gal coolers (which were small for what i was brewing) and a keggle as my boil kettle. I would just heat up my water in the keggle and then fill the MLT and mash in. Then heat up the sparge water and put into the HLT and would then drain it back into the keggle to boil.
Primary: Local Honey Mead;
Keg: "Experimental" American Ale; Kinda Nutty Brown Ale;
Bottled: "Oatie the Oatmeal Stout"; NB Saison; "666" by request; NB 115th Dream hopbursted;EdWort's Apfelwein
Up Coming: Imperial Oatmeal Stout; House IPA