Hi Kelju, thanks for joining the forum!
Bookmark Draken can be used with the virtual cockpit hidden, just like in any other Prepar3D addon aircraft. We did not include a HUD-only view as Draken does not really have a complete HUD, only a gunsight. The gunsight also has no real function in the simulation, as there is no functioning weapons system and no targeting radar.
Draken has no flaps, in the simulation the P3D/FSX flaps command is instead used to deploy the drag chute. Gear handle position can be set with a boolean variable, so you can use separate sensors/switches in your cockpit for gear up/down. See the Prepar3D SDK documentation for more information about the possibilities in Prepar3D.
There are a number of cockpit simulators in Sweden that are using real Saab 35 Draken cockpits with Prepar3D and Bookmark Draken software. I suggest that you contact them for advice regarding your cockpit project. See the links at the end of this post (web sites are in Swedish). I also recommend that you buy a developer license for P3D, it is a monthly subscription that will allow you to evaluate the full functionality of the program and the SDK at a reasonable cost. If you choose to use a different platform you can just cancel the subscription.
The standard license for Bookmark Draken is a single-user licence. This applies to the freeware FSX versions as well as the payware versions for Prepar3D. If you want to use Bookmark Draken for public entertainment you must purchase a commercial license, regardless of whether you charge the users or not. See the EULA for more information about licensing.
Kind regards /Thomas