From the photo it looks like it will clear the door. I will have to examine the caulking around the area in any case when I reinstall the anode when I de-winterize.
It occurs to me that the reason copper was used is that the ID of an Iron Nipple of the correct OD may be too small for the anode.
I normally drain the hot water heater when I open the low point drains to drain the camper. It "glugs" a bit, but I am usually doing something else while it empties in any case. I use the "paper towel in the hole and hanging off the door" technique to get the last of the water out.
Using the low point drains to drain the hot water tank avoids the occasional "whoosh" of pressurized hot water when removing the anode from a full tank.
Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW