Have you focussed on getting success with a buck converter? It is the easier type to regulate automatically, for two reasons:
(a) You turn on the switching component when output drops. Turn it off when output rises.
(b) The reference voltage (or desired output voltage) is available from the moment of powerup.
In contrast, the boost converter is not so easy to regulate.
(a) It must be kept oscillating continuously. This requires a control system which is not dependent solely on voltage sensing.
(b) A reference voltage is not available immediately at powerup, making it necessary to use some indirect manner of regulation.
That's all I can reply since I have no hands-on experience with control IC's such as UC3842.