Pump wise, the insulin is in your system for 3-4 hours anyhow, so your basal is still going to be running there in the background (just not getting more) over the hour and a half, so a small increase before, or correction after would be all that would be needed depending on if you would prefer to handle a drop during possibly due to the increase or a bit higher later needing correction.
As for the how long can we go without it's a kind of big load of random depending on what you are doing and not doing and eating or not eating and so forth. Never gone completely without any form of insulin, but used to stop taking Lantus two days before events when I was on MDI so I could flush it from me, that did need increases in my NovoRapid though to compensate for it. Longest I've had the pump turned off in suspend though or disconnected is about 3 hours though with a correction needed for the high after it went back on. Was taking no food during that time though.