Even the smallest amount of research about the cost and time to implement an ERP would indicate that it will cost a lot more than you think and customizing it to fit your specific business will take both time and a lot of money.
ERP systems are huge, extremely complex and when implemented incredibly essential to the running of the company.
If an ERP system goes down, the business stops. That is why you spend the time, money and consulting fees to have it
configured as a very high availability system. Esp when we are talking about a company of the presumed size you indicate.
The fact that you have apps running in Excel and Access is horrible, common, but very bad for a lot of reasons.
This problem might have been discovered while implementing the ERP.
Since you are already investing heavily into the ERP, making it part of that system makes the most sense to me.
The benefits of integrating these data and functionality reaps benefits across the ERP system.
Now going to Slashdot, where a whole lot of people you have non idea who is, nor what their real life experience with ERP systems
are borders upon irresponsible. Would you take the information offered by a pimply teenager on how to solve your problems? Or maybe
its an ERP expert, how do you know.
Since you work at a company that has a lot of resources, the prudent thing to do, is to find a consulting company with a proven track record
in the ERP you are working with (different from the people you already have) and pay them to come in and do a discovery of existing excel
and Access applications, map out their functionality and do an estimate for each one, how much it will cost (ballpark) to implement them in the ERP system
and give recommendations for each application as to its suitability for migration. There is likely no one answer for all of them.