I would suggest that you first read whichever ones sound most interesting to you. There isn't a secret order you can read them. If you find one is too hard, you could switch to another and see how you fare. However, if they all specify that they're suitable at a certain point, then you shouldn't have any problems.
Ragnar, your list looks interesting, but as with my previous advice, don't let yourself be overly constrained by a preconceived idea of the order of your books.
In general, I'd say that if you've made it through Roma Aeterna, go ahead and try to read whatever you want! You should have a pretty solid knowledge of Latin by that point and be able to handle most standard authors. Some will be harder than others, of course. If pressed, we could probably classify different authors/works in categories like A, B, C etc. by order of perceived difficulty.
Beyond a certain point, let your interests guide you. For example, I find De Rerum Natura to be boring and I don't read much poetry, but I do like prose and Cicero's speeches.
The right course of study is the one that you keep up with.
Horae quidem cedunt et dies et menses et anni, nec praeteritum tempus umquam revertitur nec quid sequatur sciri potest. Quod cuique temporis ad vivendum datur, eo debet esse contentus. --Cicero, De Senectute