This one has been confusing and I'm not all that familiar with these engines so looking for a little advice/direction on where to go next.  Working on a 14 Durango with the 5.7 hemi with coolant loss but no visible leak.

It overheated one day on the way to work so shut it down, let it cool, and went straight to auto parts store to get coolant as it was low.  No visible leaks at this time so I filled it up and watched it the next day.  No issues but the following day overheated again with low coolant and some coolant out of the overflow.  Filled it up a second time and ran it hard.  No visible leaks again and no overheating.  

Sat for a few days and went to check coolant and it was low again.  There was some coolant on the ground around where the overflow is.

So Far:
Oil is clean
Exhaust smells fine/no smoke
No check engine lights
Engine runs fine
New thermostat
New radiator cap

My next step is to get some dye and probably a pressure tester for the cooling system.  

Any other thoughts on what this one might be.  I did a water pump probably ~2 years ago as it was coming out of the weep hole and bearing was bad.  No issues since then.

Pressure check cold. Use the tool from any parts house.

if you find the leak, great.

if not pull the plugs and see if you can see clean or white plugs.

the steam steam cleans the plugs.

hopefully and external leak, and not head gaskets or cracked block/heads.

good luck!

Head gasket probably, the coolant from the overflow is a clue that the cooling system is getting pressure over normal in it. Does it ever miss a bit when you first start it up in the morning?

Trying to track down a pressure checker but no one seems to have one.  May have to try the ole harbor freight if I can find one to rent.

Pick up some test strips that can pick up combustion products in coolant. Also, if running with the radiator cap off, and bubbles are seen, that is an unfortunate sign.

No miss or other abnormal sounds when doing a cold start.  No smoke or sweet smell from exhaust at any point.  

Right now the radiator is full but the overflow is below the add line.  Did a heat cycle in the shop and it got up to operating temp and just stayed there.  I would assume if it is the head gasket it would pressure the system into pushing fluid past the radiator cap.  

I have not seen any bubbles with radiator cap off.  I'm letting it cool right now and going to pick up a pressure tester that I found after the wife gets home.

I posted earlier. Use that pressure check tool and report back. My thought is a 10 year old cooling system. Your rubber lines could have some issues.

Check passenger side carpet.  Is it wet?

Ran a pressure test cold.  Best I could tell the gauge dropped ~ 1/10th of a PSI over 10 minutes both times.  It's not that accurate of a gauge though.

I did a cold start after and nothing out of exhaust.

Edit:After reading some more I'm going to do a second test in the morning.  It had been up to temp about 5 hours before and the upper hose was still slightly warm which from what I found can affect the readings.

Cold test passed the PSI hold however, I did see a drip underneath the water pump coming from the gasket area.  Very small but that would explain the couple days between having issues and the fact it probably doesn't do it when hot as everything expands.

Could you maybe tighten the bolts some to try to stop the drip?

Started tear down and found 3 bolts around the leak were loose.  Retorqued all bolts to spec and reassembled.  So far no leaks but I still would like to know why they were so loose.  It's been a couple years since I put a water pump on it and no issues in that time.

Yep, re-torquing the water pump bolts is just asking for the O ring to fail.  
If the drip is coming from the weep hole, then for sure it needs a new water pump.