Visit Agra from Delhi is so easy for who ever visiting in their busy schedule , I will suggest you to all to visit taj is too easy from Delhi by Express Highway , its very fast and hassle free to reach Agra in max 3.30hr
my personal experience who visited our homestay interacting with many of them are different type of situation they are travelling like some people on their office trip in between they got some time so they planned quick day visit or over night stay and visit Taj , some are planning for day visit and going back to Delhi , or some are coming for over night and moving to Jaipur , some are interested to visit by Train, option all are convenient only but who were really keen to travel and visit the places need to explore properly that would be difficult because so many suggestion like internet is giving and drivers are suggesting or else their family, family friends or collegue so or other way they are got followed after that once it reach Agra they got panicking like for example
by road family visiting and staying our place , most of them were not started on time from delhi , its all reaching by 4-4.30 , Agrra is fully a heritage or monument based tourist city nothing is there , most of the monuments use to close by this time because they will close the ticket window on time so that inhouse occupies guest will come our on time ultimately the story is that day of the guest were gone full mess
2nd day by afternoon they have to leave for delhi back or moving jaipur or any other schedules like varanasi etc..
early morning they have to wake up and should go for a Taj visit , but the situation is different , they wake up bit later like 7-8 am and have delicious breakfast and then first visit to Taj , definitely I have to tell most of them will spend there around 2-3hrs the time will reach by 11.30-12.30noon then again the same rush and bussy schedule to cover rest of the place like Mehtabagh , Sikandra , Agra fort etc.. all in quick view as much possible they will cover by lunch and a fast driver to their other destination