LATHROP – Seth Harper pushed hard with his right leg and steered with his left. With Lathrop High School disappearing behind him, Harper forced his way down Spartan Drive towards the Lathrop Skate Park – the above-ground, composite-material attraction in the shadow of Lathrop Police Services – as construction crews put more finishing touches on the first major aspect of the Lathrop Generations Center.He had already stopped to marvel. Lathrop’s park will boast things like rails and stairs – a street skating course – that are absent from many community skate parks including in Ripon and Manteca.