Lost keys, is there any way to start it without the keys?

You really have two options; a mobile locksmith can come out and use a Lishi tool to decode the cylinder and cut a couple keys and then test to be sure they work. Anti-theft was an option on those trucks, and they can verify that as well. The other option is to go to a dealership with the title and proof that you own it as well as proof of identity and they can look up the code and check if it has antitheft using the VIN. Then they cut the keys, and you go home and test it. There is no way to start it without using the key if it has the antitheft option. That is because of the way it operates, if one with the anti-theft option is forced by bypassing the correct starting procedure the anti-theft will lock out any further attempts even if you have the correct key, it will not work at that point. To get that repaired you would replace the central timer module with a new one programmed to your VIN from the factory.
They are a single use module unless you have a full bench to remove the PROM chip and change the coding.
I suggest the smith myself; they are generally cheaper than the dealership and they come to you.