Caeser is definitely very easy as far as classical Latin is concerned. He just presents straight forward narratives in a simple style. Lots of ablative absolutes.
I don’t have a lot of experience with it, but I’ve been reading some William of Ockham lately and I find it very easy. It’s medieval Latin, and the author’s first language was English, and the word order reflects this too a great extent. I find I can sight read his philosophical texts without much difficulty. Also, the scholastic philosophy should be similar to the Thomas you’re familiar with.
For example, here is the first paragraph from “Summula Philosophiae Naturalis” which I recently started reading:
Omne compositum componitur ex partibus sine quibus esse non potest, et dependet ex causis sine quibus una pars compositi alteri non unitur. Cum igitur scientia naturalis de compositis habeat considerare, sequitur quod ad considerationem eius pertinent partes compositi et causae eiusdem. Illae autem partes compositi per se sunt materia et forma, quae vocantur principia et causae eius. Ad naturalem igitur philosophum spectat docere tam de materia quam de forma.
Here is my quick translation for reference:
Everything composite is composed out of those parts without which it cannot be, and depends on those causes without which one part of the composite cannot be joined to the others. Since, therefore, natural science needs to consider composites, it follows that the composite parts and causes pertain to the consideration of that and of the same thing. But those composite parts are through themselves matter and form, which are called the beginnings and causes of it. Therefore it behooves the natural philosopher to teach as much of matter as of form.
The only things I’ve run into so far are a few Medieval constructions, and most of those you can figure out intuitively. For example, in the last sentence “spectat” is used as an impersonal construction of obligation, and the object takes “ad”. But even if you translate it as “it looks to the natural philosopher to teach…” it still makes sense. Also, I was told that “habeat considerare” functions here (intuitively) as “has to consider”.
Besides that, keep in mind the scholastic philosophy you’re dealing with. In his preface Ockham refers to “compositum per accidens” and “compositum per se unum.” This is the difference between artifacts and natural entities. A house is a single entity through accident or chance, while fire and animals are single entities in their own nature.