In books, actually, women seldom perform caste work, with the exception of physicians:
The women of a given caste, it should be noted, often do not engage in caste work. For example, a woman in the Metalworkers does not, commonly, work at the forge, nor is a woman of the Builders likely to be found supervising the construction of fortifications. Caste membership, for Goreans, is generally a simple matter of birth; it is not connected necessarily with the performance of certain skills, nor the attainment of a given level of proficiency in such skills. To be sure, certain skills tend to be associated traditionally with certain castes, a fact which is clearly indicated in caste titles, such as the Leatherworkers, the Metalworkers, the Singers, and the Peasants.
A notable exception to the generalization that women of a given caste normally do not engage in caste work is the caste of Physicians, whose women are commonly trained, as are the boys, in the practice of medicine. Even the physicians, however, normally do not admit their women to full practice until they have borne two children. The purpose of this is to retain a high level of intelligence in the caste. Professional women, it is well understood, tend not to reproduce themselves, a situation which, over time, would be likely to produce a diminution in the quality of the caste. Concern for the future of the caste is thus evinced in this limitation by the physicians on the rights of their women to participate without delay in the caste craft. The welfare of the caste, typically, takes priority in the Gorean mind over the ambitions of specific individuals. The welfare of a larger number of individuals, as the Goreans reason, correctly or incorrectly, is more important than the welfare of a smaller number of individuals.
Fighting Slave of Gor
I think it's very possible in SL Gor to companion within the caste, it's the norm in books. Just, most people will have to stop confusing the Gorean companionship with a Gorean e.harmony.com dating.
Sometimes, for alliances and political reasons, there are exceptions to the norm but in SL Gor, characters commonly companion for love (and no alliance and interests).
So, it's not rare to meet in SL Gor the commander of a city who companioned the local seamstress who, once the contract have been signed, continued her former caste labor. Another common example is the one of an apprentice physician woman who will companion the local blacksmith (or another low caste man), will plan to give him 2 kids, then will consider she will be able work as physician, when in fact, she was expected giving children to her formal caste... (The usual problem, too, of the lack of consideration for status and ranks in SL Gor and not to mention than people tend to forget that it's the father who passes the caste).
Worse, their kids will often tend to choose a different caste. At the end, you get a family non sense caste melting pot.