MCW, if landscaping is what you enjoy doing, then do it. Really, the only equipment you need is a shovel, a rake, and a wheelbarrow. That is much less of an investment than is required for maintenance. If you need a skid steer, rent one,,,need a mortar mixer rent one, etc. As far as the truck is concerned, the gold one seems like a good deal, I would recommend a 3/4 ton any day. The repairs are a bit more expensive, but you are better off with a 3/4 ton than you are overloading a 1/2 ton and wearing it out quicker.
Now for the dump insert, (I will play devil's advocate here) What are you really planning on using it for? Mulch? Why do you need an insert for mulch? I think that an insert could come in handy, but you really don't need one. I never had one when I worked alone. Can't you use the bed of your truck in combo with the trailer you use for your maint. equipment to haul trash etc. Also, I would not recommend a dump trailer,,,in a way that is an ignorant statement because I have never owned one of those either. I just dont think they are worth the money. If you actually need a dump trailer, then get a dump truck, that way you can pull a trailer with it to haul your skid steer, chipper, trees or whatever.