Complex Internal US flight connections - advice please

We have a short trip (Tues- Sun) to New Orleans booked for Nov (work but some play!)
Managed to get 2 Gs - out via Miami (looking forward to first trip on Dreamliner). Only home Gs available on a Sunday were via Washington so have to get there in time for 6.45 pm departure.
New Orleans unfortunately not a Delta hub so no direct flights to MIA or IAD.

I have a couple of problems would value some advice.
1. Cost of internal flights seem extortionate
2. Timing of flight from New Orleans to IAD?

Sorted with AA flight from MIA to New Orleans (£120 ow seems OK) on Weds am.
Only direct flight on Sunday to IAD arrives at 3.30pm (time perfect) but is $500(!!!) ow with United. Flight seems pretty empty but only Flexible economy available.
Will a standard Y fare become available nearer the time or should I bag it now?
A Sunday flight allows extra time in New Orleans.

Other option is Delta flight to ATL on Sat eve and spend a night morning in Atlanta (worth it?)
If so what time Delta flight from ATL to IAD?
The 12.15 gets in at 1.58 - safer. The 2.58 would allow more time in ATL (worth it?) The 2.58 gets in at 4.45 but only allows a 2 hour connection (and less time in the Washington CH!) is this pushing it time wise?

First world problems I know but any advice appreciated.
Trying to balance as much leisure time as possible in a 5 day work trip with not missing the VS IAD flight on Sunday eve which would be a disaster.
So thanks for help - finally Hotels in New Orlean? Was looking at Hilton (Charles St), Le Meridien or the W. Have not met anyone who's ever been here so need some help.
Thanks very much!

In answer to 1:

Have you looked into flying to DC's other airport, DCA (Ronald Reagan Airport - no joke)? Flights are $100-$200 on average, one-way, in Y for MSY-DCA.

DCA to IAD is about 30 minutes in a cab, especially on a Sunday, and around $80-90.

In answer to 1, As someone currently living in NY, I can vouch for the high cost of internal flights to / from MSY and the east coast!... MSY for some reason is extortionate with very few flights having 'cheap' seats. ( I booked NYC to MSY return 6 months in advance and it was still over $500 in Y.)

My advice for what it's worth would be to stay in MSY until Sunday, have some fun on Frenchman street on Saturday night, enjoy your time in New Orleans and take the hit of the one way flight straight to IAD at the time which suits you. Prices do fluctuate, but Sunday is peak so I reckon there's little chance of it going down much.

In answer to 2, I vote don't ruin such a short trip with messy internal flights and transfers... (that after taxis and time wasted probably don't end up saving you that much money!) Take the direct to IAD

I would take the direct United flight that leaves MSY at 8am & arrives IAD 11:21, cost £165.60. Have a wander and some nice lunch in DC before your VS flight back in the evening. (The Nov date I selected was Sun 20th)

I have done exactly the same thing, one way on UA and bitten the cost to connect to VS at IAD. I'd rather the extra time in NO. Watch the bag charges though.

Just out of interest I checked how much extra First Class would be on that 8am from MSY to IAD, its's £100 more (£265 total) - which of course includes free luggage.