The jet range formula beloved by CFS is
SAR=TAS/EAS x EAS/Drag x 1/SFC
The nice thing about this is that it splits up the 3 important factors which each need to be maximised.
TAS/EAS is maximised by flying as high as possible.
EAS/Drag is maximised by flying at 1.32 x Vmd.
1/SFC is maximised by flying at design RPM (normally around 95%).
1.32 Vmd is a very low IAS and, at low altitude, you'd be using a lot less than 95% RPM to hold it so you need to climb to an altitude where 95% RPM gives you the right speed and this will also maximise TAS/EAS.
There's more to it than this because, at high altitude, transonic effects come in and these will reduce the best range speed.
As far as climbing is concerned, you need to keep the maximum excess power for the best climb rate. This requires a decreasing TAS and one way to achieve this is to fly constant Mach (speed of sound decreases with altitude as far as the Tropopause).