The controls are mostly based off of the Arma series, if you're familiar with those. For example, Numpad Enter toggles the external view off and on. The "typical" external camera positions that you may be used to - fly by, chase, etc. - don't exist for ToH...yet!
The HUD view comes default with the Beginner and Trainee difficulties. To turn it on with Expert you have to manually set it on the difficulty customization page.
Lights are turned off and on via in-cockpit switches - there may be keyboard commands for them, but I don't know them.
If you go to the controls page, you can scan through all the possible commands and see what they are currently mapped to.
Here's the ArmA II manual (see page 12): http://cdn.steampowered.com/Manuals/33930/ARMA2OA_manual.pdf
There are also several good ArmA 2 keyboard layout maps on the 'net that you can look up. Here's only one example: http://four-four.proboards.com/index.cgi?board=arma&action=print&thread=1685