An interesting question, and one that I might be able to give you a little bit of insight into. I would like to start with a disclaimer though: my answer is not based on statistics of the company, and as such is not an explanation of what the most likely average career would look like. Instead, it is more of an exploration of a possible path you could take in the Company based on the lives of employees I have studied.
First off, I would like to address some aspects of your question. As you specified that you wanted to sign up for a job overseas, I am going to assume that you do not want to work on a ship. Instead, I will assume you applied to work at a trading post in the Company's extensive Inter-Asian trading network.
The most obvious answer of what to expect over the next 20-30 years is, frankly, death. At the end of the 17th century, over half of the VOC's employees died in Asia. To truly have a career in the Company that lasted several decades, you'd need some luck and a hardy constitution. Let's imagine our employee is healthy and resistant to tropical diseases.
You would most probably arrive in Asia at one of the Company's central nodes. For most of the company's history, this would mean Batavia in modern day Indonesia. At the end of the 17th century, however, this could also have been somewhere in India, most likely Ceylon (modern day Sri Lanka) which was at that time allowed to maintain a direct connection to Amsterdam.
After arriving there, you had broadly two options. You could work in Batavia itself, which basically functioned as a Dutch city in Asia. I am not an expert on life in Batavia, so I will make the assumption that our imaginary employee asks to be assigned to a kantoor, a regional trading post.
As a new employee at a trading post, you would most likely start off in a fairly lowly position such as a clerk or a junior trader (onderkoopman) based on your bosses estimation of your abilities. What happens next is anyone's guess and would have depended entirely on your abilities. You would be put to work either at the central trading post in your region, or in one of the smaller trading posts subject to the central trading post. If you were, for example, employed in the Souratta region (the northwest of modern India), you could be working at the central kantoor in Souratta itself or in one of the smaller trading posts in the Souratta region. An example of such a post was the one in Ahmadabad, which was tasked with procuring Diamonds, Cloth and Saltpetre for the central trading post in Souratta. The employees in Ahmadabad would report to Souratta, which in turn reported to Batavia.
What happened next would have depended on your abilities. There are examples of people who never really rise above the lowly positions in a kantoor. Rather, these people often settled for being good at what they did, often by building up good connections with the local populace (possibly through marriage). Such employees were vital to the continued success of a kantoor, providing a stable factor in a place where many employees died or were promoted to work elsewhere. Their connections were also important to the kantoor's ability to trade and operate in a foreign country.
However, if you were ambitious and able, there was a good chance of being promoted fairly quickly. You could be promoted to senior trader (opperkoopman) or to head of one of the trade centres (often called opperhoofd or commandeur). A promotion might mean moving away to a different trade region, if the directors of the Company felt you were more useful there.
An example of how quickly an ambitious man with reasonable capabilities and a good constitution could be promoted and travel all through Asia would be Hendrick Zwaardecroon (1667-1728). He was employed by the VOC in 1684. He was initially employed as an accountant and then during a period of 5 years he was promoted to junior trader, then to trader, then to senior trader. In 1694, he was promoted to be the commander of Jaffanapatnam on Ceylon. Two years later, he was promoted be the commander of the entire coast of Malabar and was simultaneously the governor of all of Ceylon. In 1699, he was named director of Souratta. This might seem like a massive demotion, but was in fact a sign of the trust the Company had in him: Souratta was dealing with a major crisis that Zwaardecroon was deemed capable of solving. In 1703, Zwaardecroon was invited to work directly for the executive directors of the Company in Batavia. He kept being promoted in Batavia until finally, in 1718, he was named Governor-General of the Company, the highest executive function in the Dutch East India Company.
In other words, rising through the ranks of the Company was just like any other job. Ff you were ambitious, capable, did not die and had a bit of luck, the sky was the limit.
Sources:
Gaastra, F. S., De geschiedenis van de VOC (5 e druk; Leiden, 2002).
Gaastra, F. S., ‘The Organization of the VOC’ in R. Raben and H. Spijkerman ed., De archieven van de Verenigde Oostindische Compagnie: The Archives of the Dutch East India Company (1602-1795) (The Hague, 1992) pp. 11-29.
Santen, H. van, De Vereenigde Oost-Indische Compagnie in Gujarat en Hindustan, 1620-1660, Ph.D. thesis Leiden University (1982).
Stapel, F. W. Gouverneurs Generaal van Indië.