Here's how I do it:
1. heat water in brew kettle on Blichmann burner with raised legs
2. transfer hot water to 10 gallon Igloo mash tun on ground using camlock connections and silicon hose -- by using a hose, I lose very little heat;
3. dough in, correct mash temperature by stirring and adding cold water as needed;
4. put mash tun on table and let sit for 60 minutes;
5. heat sparge water in brew kettle;
6. transfer sparge water to 5 gallon Igloo HLT with camlock/hose;
7. at end of mash, put brew kettle on ground below mash tun (on table) and drain using camlock connection/hose (after vorloufing);
8. put mash tun on ground and HTL on table top and add batch sparge water + stir;
9. put mash tun back on table and drain into brew kettle on ground;
10. repeat steps 8 & 9 if batch sparging twice;
11. put full brew kettle on burner and begin boil.
Alternatively, for steps 6 & 7, you could use your brew kettle as your HLT and simply drain (lauter) your mash tun into a 5 gallon bucket after the mash; you could then put your mash tun on the ground under your brew kettle and transfer your sparge water straight from the brew kettle into the mash tun, stir and drain into the 5 gallon bucket. Once your brew kettle was freed up during the second batch sparge, you could pour the wort from the 5 gallon bucket into your brew kettle.