I use LNM as well and have the Navigraph beta. I tend now (with the Beta) to flight plan in MSFS world map, save the plan, then load into LNM to use as a moving map - much better than the VFR map in MSFS.
For my all capitals mega trip, I’ve been using great circle mapper to work out the shortest route - plus a complicated excel spreadsheet and VBA…I know - but it is something to do in the cruise that isn’t housework 
My best route is this on GCM:
109,078 miles
I’m planning on doing this in the Longitude - should be just able to do the longest leg which is Mexico City to Papeete in French Polynesia
If you want the flight plan, click here:
Flight Plan
UTDD-UTTT-UCFM-UACC-UTAA-OIII-UBBB-UGTB-UDYZ-ORBI-OKBK-OBBI-OOMS-OMAA-OTHH-OERK-OJAI-LLJR-OSDI-OLBA-LCEN-LTAC-LRBS-LBSF-LWSK-BKPR-LATI-LYPG-LQSA-LYBE-LHBP-LZIB-LOWW-LDZA-LJLJ-LIPR-LIRE-LMML-HLLT-DTTA-DAAG-LESU-LEMD-LXGB-GMME-LPPT-EGJB-EGLL-EHAM-EBBR-LFPG-ELLX-LSZB-LSZE-LKPR-EDDB-EKCH-ENGM-ESSA-EFHK-EETN-EVRA-EPWA-EYVI-UMMS-UUEE-UKBB-LUKK-LGAV-HECA-HSSS-HHAS-HDAM-HAAB-HSSJ-HUEN-HRYR-HBBA-HTDO-HKJK-HCMM-FSIA-FMCH-FMCZ-FIMP-FMEE-FMMI-FQMA-FDMS-FXMM-FAWB-FVHA-FWKI-FLKK-FBSK-FYWH-FNLU-FZAA-FCBB-FEFF-FKYS-FGSL-FOOL-FPST-DBBB-DXXX-DGAA-DIYO-GLRB-GFLL-GUCY-GGOV-GBYD-GOOY-GVNP-GQNO-GABS-DFFD-DRRN-DNAA-FTTJ-EIDW-EKVG-BIKE-BGGH-LFVP-CYOW-KIAD-TXKF-MBPV-MTPP-MDSD-TJSJ-TIST-TUPJ-TQPF-TNCM-TKPK-TAPA-TRPG-TFFB-TDCF-TFFF-TLPC-TVSA-TBPB-TGPY-TTPP-SOCA-SMJP-SYCJ-SVMI-TNCC-TNCA-MKJP-MYNN-MUHA-MWCR-MZBZ-MGGT-MSLP-MHTG-MNMG-MROC-MPMG-SKBO-SEQM-SPJC-SLLP-SCEL-SFAL-SUMU-SAEZ-SGAS-SBBR-MMMX-NTAA-NCRG-NIUE-NSTU-NSFA-NFTF-NFNA-NGFU-NGTA-PKMJ-ANYN-AGGH-NVSV-NWWW-YSNF-NZWN-YSCB-AYPY-PTPN-PGSN-PGUM-PTRO-RPLL-VHHH-VMMC-VVNB-VLVT-VTBS-VDPP-WMKK-WSSS-YPCC-WIII-WPDL-WBSB-RCTP-RJTT-RKSI-ZKPY-ZBAA-ZMUB-ZULS-VQPR-VGHS-VYYY-VCBI-VRMM-VNKT-VIDP-OPIS-OAKB-UTDD