I have a LMT 2000 defender that I never used. It has a 16 inch barrel, and the standard fixed front sight. The handguard is the standard black plastic.
I wanted to have a rail on it to support a MS4 button swivels sling and a Atlas bipod. I have that on my go to troy upper, but that one is Alpha rail, and I think Magpul points would be easier. Anyway what would be a good solution? Persoanlly I never "built" and upper nut I am handy with tools. So if the job needs specialty tools I hope you can suggest that also. I tried looking at youtube etc, and there are too many choices. I have the money to cry once, but I like to always be conservative. I am thinking free float is best for accuracy. I imagine it will be used against ground hogs the most.

I'm pretty sure the LMT is a carbine gas system which limits you on space (7") with the fixed front sight base.

I've seen a few custom tubes that cut out a slot for the front sight to stick through but other than that you have limited choices, at least for what I would like.

If you want to cut off the front sight base and just use it as a pinned gas block, you can use any rail/tube you like. It's probably the best way to go unless you shoot irons a lot.

I have a Daniel Defense Omega rail that I would make you a deal on but I don't recommend it, that's why it's not on my Colt 6720. On that one I use a MagPul SL plastic hand guard but it doesn't have what you're looking for.

Leaving the front sight post- Troly Delta Rail. The only real choice, they are good handguards. True drop in, takes less than 5 minutes.

Switching to a low pro gas block or chopping the GB- Geissele MK16 or better the Hodge Defense Wedgelok Rail. Both have minimal Rail deflection under load (read stiff) with an excellent barrel nut/rail interface. The Hodge Wedgelok is stiffer and feels better in the hand.