What to do? The answer is to "putz with setups."
So I proceeded to (a) look at what it would cost to roll out both of these spreads, improving each of them by a single strike (i.e., rolling the 111/114 to 112/115 and the 115/118 to the 116/119) in various expiries; (b) look at what it would cost to roll both spreads out, but improving only the strikes of the 111/114, also in various expiries; and (c) what I can get for credit for the sale of an oppositional short put credit spread against the rolled out positions.
So, here's the plan I came up with after looking at all the possibilities: I'm looking to roll out the 111/114 up and out to the June 17th expiry 115/118 for a 1.07 debit and the 115/118 "sideways" or "as is" and out to the June 17th expiry for a .57 debit. This will essentially "merge" the two spreads into a single June 17th 115/118 short call spread. The total cost to roll these two spreads is 1.64 (assuming I can get a fill of both at these prices), which means that I will want to sell a short credit spread against these rolled out positions for something in excess of 1.64.
The June 17th 111/114 (rather ironically, since this is what the short call side of my iron condor started out at) fits this bill, as it will bring in an .82 credit/contract. (Keep in mind that the 115/118 is now "times 2," since I'm going to be merging the March 18th 111/114 with the 115/118).
The result will be a June 17th 111/114/115/118 GLD iron condor. Naturally, were this to be an "original" setup, it would be low probability and probably qualify as "horrible." The only way it completely works out at expiry is for price to magically settle between 114 and 115 (the short put and short call strikes, respectively). However, we these broken setups, the goal isn't to roll into an ideal 70%+ probability of profit setup, but rather to gradually mitigate loss and to slowly work it into a state where you an exit one side of the trade at or near max profit, and then to exit the other in the same state ... . Of course, sometimes it takes longer than you'd like.
(A Side Note: I considered adding risk here on this up move with an additional short call spread above current price (e.g., an April 15th 129/130 GLD short call spread currently goes for a .35/contract credit), but thought the better of it, since the jury's still out as to whether it will break 120 ... ).