It seems most places, the procedure is to fly runway heading as the engineers have analyzed the surrounding terrain for obstacle clearance. But how far out are they required to analyze.
Do they, now ?
Things will vary according to jurisdiction but, as a general thought, consider -
(a) Type A charts will go out a reasonable distance (but no where near what is required for a critical straight ahead departure. They tell you a story about the rocky bits but have ZERO interest in whether your particular aeroplane might/might not be able to miss them ..
(b) if terrain is critical, the pilot has NO WAY of doing the sums on the fly. Either the operator has it done appropriately or you are sailing close to the wind each and every takeoff
Generally the approach adopted by reasonable operators is to divide the runway database into at least three paddocks -
(a) easy - there will be some SOP recovery procedure
(b) not so easy with one of two awkward obstacles - there will be a specific, sort of standardised procedure - eg, climb to X ft, turn to the Y aid and climb in the pattery for the let down
(c) nasty - a full blown escape procedure.
However, if your operator hasn't given you a specific and credible procedure for a difficult runway, oh dear ...
As to how far out a straight procedure might go ? .. for a critical twin, how about 50 nm or so ?