With CPU clock speeds stagnating over the last few years, ongoing advances in computing power and capabilities are being supported through increasing multi- and many-core parallelism. The resulting cost of locally maintaining large-scale computing infrastructure, combined with the need to perform increasingly large simulations, is leading to the wider use of alternative models of accessing infrastructure, such as the use of Infrastructure-as-a-Service (IaaS) cloud platforms. The diversity of platforms and the methods of interacting with them can make using them with complex scientific HPC codes difficult for users. In this position paper, we discuss our approaches to tackling these challenges on heterogeneous resources. As an example of the application of these approaches we use Nekkloud, our web-based interface for simplifying job specification and deployment of the Nektar++ high-order finite element HPC code. We also present results from a recent Nekkloud evaluation workshop undertaken with a group of Ph.D. student users of Nektar++.