, I think this is possible, but You need observe two obstacles to achieve this.
First, I don't remember if R-J2 controllers accept text files. So You will first need to convert these text files, on .ls or .pe format, to .tp (binary format). To to this, You will need Roboguide, its older brother, WinOLPC, a command line utility called MakeTP (that You can find on the installation folders of the two previously mentioned programs), or even an old program called R-J Translator. The minor software version supported by Roboguide is V5/R-J3. R-J Translator supports R-J2 programs, but has some problems with SPOT commands. And so on. So You will need to make some trial and error tests to determine what is the best option for You.
The second part is uploading the programs on R-J2 controller. Some of them had a special compact flash slot on their bases, but if I recall correctly, You need a specific type of compact flash card, and also a special adapter.
The second and easiest way to upload your programs is using serial connection and KFloppy utility. But serial transfer is a lengthy procedure, subject to several types of errors, You will need to find a good serial<>USB adapter (or an old laptop), and so on. Again, trial and error.