Like everything it's all down to individual ability - some people can, some people can't. The only real arbiters of this are ourselves
provided we have the ability to be totally honest with ourselves (which will rule out some of the ego's out there
Scenario - just renewed twin rating after a four year lapse (Seneca). Thrown keys to an Aztec Turbo with the comment "Grab an hour by yourself so that you're happy, you can take the boss to EGCC Thursday".
Two hours with the POH, another hour familiarising myself with the aircraft inside and out, time to start engines. One hour later, back on the ground - job done. Providing you approach each phase of the flight from start to shut down analytically, and learn the relevant speeds and configurations beforehand there is no "mystique" to moving onto other aircraft by yourself.
But you have to be honest about your own abilities and approach to the situation first (I find being an easily scared pessimist helps big time!
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