You don't mention your LANDesk version. I would at least try a provisioning task since it is the easiest way to survive reboots. I just used a provisioning tasks that installs a crap load of apps and does at least 3 reboots.
I am currently running LDMS 8.8 SP3.
I do not have any experience with provisioning tasks, are there any documents you recommend reading?
After reading a few community threads it appears this works similar to a push delivery. The will not work due to the nature of the environment. The machines I am having trouble with are field users who I cannot guarantee will be online at a specific time.
Provisioning will not work via the gateway as you mentioned, despite it looking like a policy, it really is a push, I wish they could add true "policy" delivery to it as we do not use Provisioning for OS Deployment, but would like to use it for Software Dist. as it allows more advanced options.
My question for you is, where do you keep your SEP package? If it is NOT on the core or you have not hacked your IIS, the Gateway will not allow your clients to go off to a package server, it only allows your clients to get to the core.
If it is not on the Core, you could add a package location to the ldlogon folder and this "should" work.
We have top notch guy here that I lean on sometimes for complicated packages, and he has in the past created packages that install a service and this service then takes over the installation of various applications. Unless you are or have such a guru that is not always feasible.
The SEP package is in on the core where clients should be able to access via the gateway.
I have used this command line for provisioning with success and can call it as a policy:
\\coreservername\ldlogon\Provisioning\windows\ldProvision.exe -c CORESERVERNAME