I think it's pretty clear that 'Arry will accept the job soon to begin end May, with Pearce taking control until then. The back room staff (Bond, Sherwood, Jordan, etc) are likely to go with him from the sounds of it, so I imagine they'll be spread between Spurs & England for continuity's sake from now on.
Rednknapp's said managing your country is the ultimate honour, and has also pointed out he's 64 & his health's not what it was. When nearing retirement age why not accept a promotion to The Top Job & work less hours than he does now? Do that for a couple of years, have a nice run (let's be honest, no-one expects England to do well for at least the next 5 years, so the pressure can't be that great), and spend a bit more time relaxing with his family.
We'll miss him, but we can't be surprised - we've been preparing ourselves for it for years.