  We study a generalized quantum spin ladder with staggered long range
interactions that decay as a power-law with exponent $\alpha$. Using large
scale quantum Monte Carlo (QMC) and the density matrix renormalization group
(DMRG) simulations, we show that this model undergoes a transition from a
rung-dimer phase characterized by a non-local string order parameter, to a
symmetry broken N\'eel phase. We find evidence that the transition is second
order.In the magnetically ordered phase, the spectrum exhibits gapless modes,
while excitations in the gapped phase are well described in terms of triplons
-- bound states of spinons across the legs. We obtain the momentum resolved
spin dynamic structure factor numerically and find a well defined triplon band
evolves into a gapless magnon dispersion through the transition. We further
discuss the possibility of deconfined criticality in this model.
