In the Book of Mormon the infinitival to is typically repeated for conjuncts, as here in Jacob 7:2 and in the following instances where “to preach” is conjoined with other infinitive verb forms:
The 1892 RLDS edition accidentally omitted the repeated to here in Jacob 7:2, but the 1908 RLDS edition restored it to the RLDS text.
Summary: Maintain the repeated infinitival to wherever it is supported by the earliest textual sources.